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Fail to set private static final variable in Android #44

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BaoBaoJianqiang opened this issue Dec 12, 2017 · 5 comments
Open

Fail to set private static final variable in Android #44

BaoBaoJianqiang opened this issue Dec 12, 2017 · 5 comments

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@BaoBaoJianqiang
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BaoBaoJianqiang commented Dec 12, 2017

In Android, jOOR doesn't work when reflect final field by jOOR.

Because Field class in Android is different from the same file in JDK, as follows, there is no accessFlags field in this class:

/*
 * Copyright (C) 2014 The Android Open Source Project
 * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang.reflect;

import sun.reflect.CallerSensitive;
import sun.reflect.Reflection;
import java.lang.annotation.Annotation;
import java.util.Map;
import com.android.dex.Dex;
import libcore.reflect.GenericSignatureParser;
import java.util.List;


/**
 * A {@code Field} provides information about, and dynamic access to, a
 * single field of a class or an interface.  The reflected field may
 * be a class (static) field or an instance field.
 *
 * <p>A {@code Field} permits widening conversions to occur during a get or
 * set access operation, but throws an {@code IllegalArgumentException} if a
 * narrowing conversion would occur.
 *
 * @see Member
 * @see java.lang.Class
 * @see java.lang.Class#getFields()
 * @see java.lang.Class#getField(String)
 * @see java.lang.Class#getDeclaredFields()
 * @see java.lang.Class#getDeclaredField(String)
 *
 * @author Kenneth Russell
 * @author Nakul Saraiya
 */
public final
class Field extends AccessibleObject implements Member {

    private int accessFlags;
    private Class<?> declaringClass;
    private int dexFieldIndex;
    private int offset;
    private Class<?> type;

    private Field() {
    }

    /**
     * Returns the {@code Class} object representing the class or interface
     * that declares the field represented by this {@code Field} object.
     */
    public Class<?> getDeclaringClass() {
        return declaringClass;
    }

    /**
     * Returns the name of the field represented by this {@code Field} object.
     */
    public String getName() {
        if (dexFieldIndex == -1) {
            // Proxy classes have 1 synthesized static field with no valid dex index.
            if (!declaringClass.isProxy()) {
                throw new AssertionError();
            }
            return "throws";
        }
        Dex dex = declaringClass.getDex();
        int nameIndex = dex.nameIndexFromFieldIndex(dexFieldIndex);
        return declaringClass.getDexCacheString(dex, nameIndex);
    }

    /**
     * Returns the Java language modifiers for the field represented
     * by this {@code Field} object, as an integer. The {@code Modifier} class should
     * be used to decode the modifiers.
     *
     * @see Modifier
     */
    public int getModifiers() {
        return accessFlags & 0xffff;  // mask out bits not used by Java
    }

    /**
     * Returns {@code true} if this field represents an element of
     * an enumerated type; returns {@code false} otherwise.
     *
     * @return {@code true} if and only if this field represents an element of
     * an enumerated type.
     * @since 1.5
     */
    public boolean isEnumConstant() {
        return (getModifiers() & Modifier.ENUM) != 0;
    }

    /**
     * Returns {@code true} if this field is a synthetic
     * field; returns {@code false} otherwise.
     *
     * @return true if and only if this field is a synthetic
     * field as defined by the Java Language Specification.
     * @since 1.5
     */
    public boolean isSynthetic() {
        return Modifier.isSynthetic(getModifiers());
    }

    /**
     * Returns a {@code Class} object that identifies the
     * declared type for the field represented by this
     * {@code Field} object.
     *
     * @return a {@code Class} object identifying the declared
     * type of the field represented by this object
     */
    public Class<?> getType() {
        return type;
    }

    /**
     * Returns a {@code Type} object that represents the declared type for
     * the field represented by this {@code Field} object.
     *
     * <p>If the {@code Type} is a parameterized type, the
     * {@code Type} object returned must accurately reflect the
     * actual type parameters used in the source code.
     *
     * <p>If the type of the underlying field is a type variable or a
     * parameterized type, it is created. Otherwise, it is resolved.
     *
     * @return a {@code Type} object that represents the declared type for
     *     the field represented by this {@code Field} object
     * @throws GenericSignatureFormatError if the generic field
     *     signature does not conform to the format specified in
     *     <cite>The Java&trade; Virtual Machine Specification</cite>
     * @throws TypeNotPresentException if the generic type
     *     signature of the underlying field refers to a non-existent
     *     type declaration
     * @throws MalformedParameterizedTypeException if the generic
     *     signature of the underlying field refers to a parameterized type
     *     that cannot be instantiated for any reason
     * @since 1.5
     */
    public Type getGenericType() {
        String signatureAttribute = getSignatureAttribute();
        ClassLoader cl = declaringClass.getClassLoader();
        GenericSignatureParser parser = new GenericSignatureParser(cl);
        parser.parseForField(declaringClass, signatureAttribute);
        Type genericType = parser.fieldType;
        if (genericType == null) {
            genericType = getType();
        }
        return genericType;
    }

    private String getSignatureAttribute() {
        String[] annotation = getSignatureAnnotation();
        if (annotation == null) {
            return null;
        }
        StringBuilder result = new StringBuilder();
        for (String s : annotation) {
            result.append(s);
        }
        return result.toString();
    }
    private native String[] getSignatureAnnotation();


    /**
     * Compares this {@code Field} against the specified object.  Returns
     * true if the objects are the same.  Two {@code Field} objects are the same if
     * they were declared by the same class and have the same name
     * and type.
     */
    public boolean equals(Object obj) {
        if (obj != null && obj instanceof Field) {
            Field other = (Field)obj;
            return (getDeclaringClass() == other.getDeclaringClass())
                && (getName() == other.getName())
                && (getType() == other.getType());
        }
        return false;
    }

    /**
     * Returns a hashcode for this {@code Field}.  This is computed as the
     * exclusive-or of the hashcodes for the underlying field's
     * declaring class name and its name.
     */
    public int hashCode() {
        return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
    }

    /**
     * Returns a string describing this {@code Field}.  The format is
     * the access modifiers for the field, if any, followed
     * by the field type, followed by a space, followed by
     * the fully-qualified name of the class declaring the field,
     * followed by a period, followed by the name of the field.
     * For example:
     * <pre>
     *    public static final int java.lang.Thread.MIN_PRIORITY
     *    private int java.io.FileDescriptor.fd
     * </pre>
     *
     * <p>The modifiers are placed in canonical order as specified by
     * "The Java Language Specification".  This is {@code public},
     * {@code protected} or {@code private} first, and then other
     * modifiers in the following order: {@code static}, {@code final},
     * {@code transient}, {@code volatile}.
     */
    public String toString() {
        int mod = getModifiers();
        return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
            + getTypeName(getType()) + " "
            + getTypeName(getDeclaringClass()) + "."
            + getName());
    }

    /**
     * Returns a string describing this {@code Field}, including
     * its generic type.  The format is the access modifiers for the
     * field, if any, followed by the generic field type, followed by
     * a space, followed by the fully-qualified name of the class
     * declaring the field, followed by a period, followed by the name
     * of the field.
     *
     * <p>The modifiers are placed in canonical order as specified by
     * "The Java Language Specification".  This is {@code public},
     * {@code protected} or {@code private} first, and then other
     * modifiers in the following order: {@code static}, {@code final},
     * {@code transient}, {@code volatile}.
     *
     * @return a string describing this {@code Field}, including
     * its generic type
     *
     * @since 1.5
     */
    public String toGenericString() {
        int mod = getModifiers();
        Type fieldType = getGenericType();
        return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
            +  ((fieldType instanceof Class) ?
                getTypeName((Class)fieldType): fieldType.toString())+ " "
            + getTypeName(getDeclaringClass()) + "."
            + getName());
    }

    /**
     * Returns the value of the field represented by this {@code Field}, on
     * the specified object. The value is automatically wrapped in an
     * object if it has a primitive type.
     *
     * <p>The underlying field's value is obtained as follows:
     *
     * <p>If the underlying field is a static field, the {@code obj} argument
     * is ignored; it may be null.
     *
     * <p>Otherwise, the underlying field is an instance field.  If the
     * specified {@code obj} argument is null, the method throws a
     * {@code NullPointerException}. If the specified object is not an
     * instance of the class or interface declaring the underlying
     * field, the method throws an {@code IllegalArgumentException}.
     *
     * <p>If this {@code Field} object is enforcing Java language access control, and
     * the underlying field is inaccessible, the method throws an
     * {@code IllegalAccessException}.
     * If the underlying field is static, the class that declared the
     * field is initialized if it has not already been initialized.
     *
     * <p>Otherwise, the value is retrieved from the underlying instance
     * or static field.  If the field has a primitive type, the value
     * is wrapped in an object before being returned, otherwise it is
     * returned as is.
     *
     * <p>If the field is hidden in the type of {@code obj},
     * the field's value is obtained according to the preceding rules.
     *
     * @param object object from which the represented field's value is
     * to be extracted
     * @return the value of the represented field in object
     * {@code obj}; primitive values are wrapped in an appropriate
     * object before being returned
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof).
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     */
    public native Object get(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance {@code boolean} field.
     *
     * @param object the object to extract the {@code boolean} value
     * from
     * @return the value of the {@code boolean} field
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code boolean} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native boolean getBoolean(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance {@code byte} field.
     *
     * @param object the object to extract the {@code byte} value
     * from
     * @return the value of the {@code byte} field
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code byte} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native byte getByte(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code char} or of another primitive type convertible to
     * type {@code char} via a widening conversion.
     *
     * @param object the object to extract the {@code char} value
     * from
     * @return the value of the field converted to type {@code char}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code char} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see Field#get
     */
    public native char getChar(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code short} or of another primitive type convertible to
     * type {@code short} via a widening conversion.
     *
     * @param object the object to extract the {@code short} value
     * from
     * @return the value of the field converted to type {@code short}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code short} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native short getShort(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code int} or of another primitive type convertible to
     * type {@code int} via a widening conversion.
     *
     * @param object the object to extract the {@code int} value
     * from
     * @return the value of the field converted to type {@code int}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code int} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native int getInt(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code long} or of another primitive type convertible to
     * type {@code long} via a widening conversion.
     *
     * @param object the object to extract the {@code long} value
     * from
     * @return the value of the field converted to type {@code long}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code long} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native long getLong(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code float} or of another primitive type convertible to
     * type {@code float} via a widening conversion.
     *
     * @param object the object to extract the {@code float} value
     * from
     * @return the value of the field converted to type {@code float}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code float} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see Field#get
     */
    public native float getFloat(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Gets the value of a static or instance field of type
     * {@code double} or of another primitive type convertible to
     * type {@code double} via a widening conversion.
     *
     * @param object the object to extract the {@code double} value
     * from
     * @return the value of the field converted to type {@code double}
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is inaccessible.
     * @exception IllegalArgumentException  if the specified object is not
     *              an instance of the class or interface declaring the
     *              underlying field (or a subclass or implementor
     *              thereof), or if the field value cannot be
     *              converted to the type {@code double} by a
     *              widening conversion.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#get
     */
    public native double getDouble(Object object)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the field represented by this {@code Field} object on the
     * specified object argument to the specified new value. The new
     * value is automatically unwrapped if the underlying field has a
     * primitive type.
     *
     * <p>The operation proceeds as follows:
     *
     * <p>If the underlying field is static, the {@code obj} argument is
     * ignored; it may be null.
     *
     * <p>Otherwise the underlying field is an instance field.  If the
     * specified object argument is null, the method throws a
     * {@code NullPointerException}.  If the specified object argument is not
     * an instance of the class or interface declaring the underlying
     * field, the method throws an {@code IllegalArgumentException}.
     *
     * <p>If this {@code Field} object is enforcing Java language access control, and
     * the underlying field is inaccessible, the method throws an
     * {@code IllegalAccessException}.
     *
     * <p>If the underlying field is final, the method throws an
     * {@code IllegalAccessException} unless {@code setAccessible(true)}
     * has succeeded for this {@code Field} object
     * and the field is non-static. Setting a final field in this way
     * is meaningful only during deserialization or reconstruction of
     * instances of classes with blank final fields, before they are
     * made available for access by other parts of a program. Use in
     * any other context may have unpredictable effects, including cases
     * in which other parts of a program continue to use the original
     * value of this field.
     *
     * <p>If the underlying field is of a primitive type, an unwrapping
     * conversion is attempted to convert the new value to a value of
     * a primitive type.  If this attempt fails, the method throws an
     * {@code IllegalArgumentException}.
     *
     * <p>If, after possible unwrapping, the new value cannot be
     * converted to the type of the underlying field by an identity or
     * widening conversion, the method throws an
     * {@code IllegalArgumentException}.
     *
     * <p>If the underlying field is static, the class that declared the
     * field is initialized if it has not already been initialized.
     *
     * <p>The field is set to the possibly unwrapped and widened new value.
     *
     * <p>If the field is hidden in the type of {@code obj},
     * the field's value is set according to the preceding rules.
     *
     * @param object the object whose field should be modified
     * @param value the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     */
    public native void set(Object object, Object value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code boolean} on the specified object.
     * This method is equivalent to
     * {@code set(obj, zObj)},
     * where {@code zObj} is a {@code Boolean} object and
     * {@code zObj.booleanValue() == z}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setBoolean(Object object, boolean value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code byte} on the specified object.
     * This method is equivalent to
     * {@code set(obj, bObj)},
     * where {@code bObj} is a {@code Byte} object and
     * {@code bObj.byteValue() == b}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setByte(Object object, byte value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code char} on the specified object.
     * This method is equivalent to
     * {@code set(obj, cObj)},
     * where {@code cObj} is a {@code Character} object and
     * {@code cObj.charValue() == c}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setChar(Object object, char value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code short} on the specified object.
     * This method is equivalent to
     * {@code set(obj, sObj)},
     * where {@code sObj} is a {@code Short} object and
     * {@code sObj.shortValue() == s}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setShort(Object object, short value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as an {@code int} on the specified object.
     * This method is equivalent to
     * {@code set(obj, iObj)},
     * where {@code iObj} is a {@code Integer} object and
     * {@code iObj.intValue() == i}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setInt(Object object, int value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code long} on the specified object.
     * This method is equivalent to
     * {@code set(obj, lObj)},
     * where {@code lObj} is a {@code Long} object and
     * {@code lObj.longValue() == l}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setLong(Object object, long value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code float} on the specified object.
     * This method is equivalent to
     * {@code set(obj, fObj)},
     * where {@code fObj} is a {@code Float} object and
     * {@code fObj.floatValue() == f}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setFloat(Object object, float value)
            throws IllegalAccessException, IllegalArgumentException;

    /**
     * Sets the value of a field as a {@code double} on the specified object.
     * This method is equivalent to
     * {@code set(obj, dObj)},
     * where {@code dObj} is a {@code Double} object and
     * {@code dObj.doubleValue() == d}.
     *
     * @param object the object whose field should be modified
     * @param value   the new value for the field of {@code obj}
     * being modified
     *
     * @exception IllegalAccessException    if this {@code Field} object
     *              is enforcing Java language access control and the underlying
     *              field is either inaccessible or final.
     * @exception IllegalArgumentException  if the specified object is not an
     *              instance of the class or interface declaring the underlying
     *              field (or a subclass or implementor thereof),
     *              or if an unwrapping conversion fails.
     * @exception NullPointerException      if the specified object is null
     *              and the field is an instance field.
     * @exception ExceptionInInitializerError if the initialization provoked
     *              by this method fails.
     * @see       Field#set
     */
    public native void setDouble(Object object, double value)
            throws IllegalAccessException, IllegalArgumentException;

    /*
     * Utility routine to paper over array type names
     */
    static String getTypeName(Class<?> type) {
        if (type.isArray()) {
            try {
                Class<?> cl = type;
                int dimensions = 0;
                while (cl.isArray()) {
                    dimensions++;
                    cl = cl.getComponentType();
                }
                StringBuffer sb = new StringBuffer();
                sb.append(cl.getName());
                for (int i = 0; i < dimensions; i++) {
                    sb.append("[]");
                }
                return sb.toString();
            } catch (Throwable e) { /*FALLTHRU*/ }
        }
        return type.getName();
    }

    /**
     * @throws NullPointerException {@inheritDoc}
     * @since 1.5
     */
    @Override public <A extends Annotation> A getAnnotation(Class<A> annotationType) {
        if (annotationType == null) {
            throw new NullPointerException("annotationType == null");
        }
        return getAnnotationNative(annotationType);
    }
    private native <A extends Annotation> A getAnnotationNative(Class<A> annotationType);

    @Override public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) {
        if (annotationType == null) {
            throw new NullPointerException("annotationType == null");
        }
        return isAnnotationPresentNative(annotationType);
    }
    private native boolean isAnnotationPresentNative(Class<? extends Annotation> annotationType);

    /**
     * @since 1.5
     */
    @Override public native Annotation[] getDeclaredAnnotations();

    /**
     * Returns the index of this field's ID in its dex file.
     *
     * @hide
     */
    public int getDexFieldIndex() {
        return dexFieldIndex;
    }

    /**
     * Returns the offset of the field within an instance, or for static fields, the class.
     *
     * @hide
     */
    public int getOffset() {
        return offset;
    }
}
@lukaseder lukaseder added this to the Version 0.9.8 milestone Dec 13, 2017
@lukaseder lukaseder changed the title Fail to set private static final variable Fail to set private static final variable in Android Dec 13, 2017
@lukaseder
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Thanks for your report.

Indeed, jOOR (as all the other jOO* libraries) are currently not integration tested for use on Android. We can certainly work around this specific problem, but rest assured that we currently have no intention of formally supporting Android at this point.

Would you mind providing a minimal, complete, verifiable example that helps reproducing the issue? Currently, there's not even a stack trace to help track down the specific call inside of jOOR which fails for you on Android

@BaoBaoJianqiang
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I can give you a demo, can you run it in your environment?

@lukaseder
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I don't know :-) Give me instructions on how to set up this environment. If it only takes little time, I'll have a look.

@ooxi
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ooxi commented Dec 27, 2017

While not having looked to close at the source you have posted, I have had problems with private static final variables before. Most likely the compiler will have your variable already inlined, thus changing the variable will not have any effect.

class Test {
    private static final int value = 3;

    public int getValue() {
        return value;
    }
}

If you change the value using reflection, most likely getValue will still return 3 nevertheless.

@lukaseder
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@ooxi: While that's certainly a problem that may arise, I think the issue here is the fact that Android's reflection API differs from the JDK's

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