http://www.javassist.org/: Javassist (JAVA programming ASSISTant) makes Java bytecode manipulation simple. It is a class library for editing bytecodes in Java. (Shigeru Chiba, www.javassist.org) 
/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later,
 * or the Apache License Version 2.0.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package javassist.bytecode;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;

import javassist.CannotCompileException;


ClassFile represents a Java .class file, which
consists of a constant pool, methods, fields, and attributes.

For example,


ClassFile cf = new ClassFile(false, "test.Foo", null);
cf.setInterfaces(new String[] { "java.lang.Cloneable" });
FieldInfo f = new FieldInfo(cf.getConstPool(), "width", "I");
f.setAccessFlags(AccessFlag.PUBLIC);
cf.addField(f);
cf.write(new DataOutputStream(new FileOutputStream("Foo.class")));



This code generates a class file Foo.class for the following class:


package test;
class Foo implements Cloneable {
    public int width;
}



See Also:
/**
 * <code>ClassFile</code> represents a Java <code>.class</code> file, which
 * consists of a constant pool, methods, fields, and attributes.
 *
 * <p>For example,</p>
 * <blockquote><pre>
 * ClassFile cf = new ClassFile(false, "test.Foo", null);
 * cf.setInterfaces(new String[] { "java.lang.Cloneable" });
 *
 * FieldInfo f = new FieldInfo(cf.getConstPool(), "width", "I");
 * f.setAccessFlags(AccessFlag.PUBLIC);
 * cf.addField(f);
 *
 * cf.write(new DataOutputStream(new FileOutputStream("Foo.class")));
 * </pre></blockquote>
 * <p>This code generates a class file <code>Foo.class</code> for the following class:</p>
 * <blockquote><pre>
 * package test;
 * class Foo implements Cloneable {
 *     public int width;
 * }
 * </pre></blockquote>
 *
 * @see FieldInfo
 * @see MethodInfo
 * @see ClassFileWriter
 * @see javassist.CtClass#getClassFile()
 * @see javassist.ClassPool#makeClass(ClassFile)
 */
public final class ClassFile {
    int major, minor; // version number
    ConstPool constPool;
    int thisClass;
    int accessFlags;
    int superClass;
    int[] interfaces;
    List<FieldInfo> fields;
    List<MethodInfo> methods;
    List<AttributeInfo> attributes;
    String thisclassname; // not JVM-internal name
    String[] cachedInterfaces;
    String cachedSuperclass;

    
The major version number of class files
for JDK 1.1.

/**
     * The major version number of class files
     * for JDK 1.1.
     */
    public static final int JAVA_1 = 45;

    
The major version number of class files
for JDK 1.2.

/**
     * The major version number of class files
     * for JDK 1.2.
     */
    public static final int JAVA_2 = 46;

    
The major version number of class files
for JDK 1.3.

/**
     * The major version number of class files
     * for JDK 1.3.
     */
    public static final int JAVA_3 = 47;

    
The major version number of class files
for JDK 1.4.

/**
     * The major version number of class files
     * for JDK 1.4.
     */
    public static final int JAVA_4 = 48;

    
The major version number of class files
for JDK 1.5.

/**
     * The major version number of class files
     * for JDK 1.5.
     */
    public static final int JAVA_5 = 49;

    
The major version number of class files
for JDK 1.6.

/**
     * The major version number of class files
     * for JDK 1.6.
     */
    public static final int JAVA_6 = 50;

    
The major version number of class files
for JDK 1.7.

/**
     * The major version number of class files
     * for JDK 1.7.
     */
    public static final int JAVA_7 = 51;

    
The major version number of class files
for JDK 1.8.

/**
     * The major version number of class files
     * for JDK 1.8.
     */
    public static final int JAVA_8 = 52;

    
The major version number of class files
for JDK 1.9.

/**
     * The major version number of class files
     * for JDK 1.9.
     */
    public static final int JAVA_9 = 53;

    
The major version number of class files
for JDK 10.

/**
     * The major version number of class files
     * for JDK 10.
     */
    public static final int JAVA_10 = 54;

    
The major version number of class files
for JDK 11.

/**
     * The major version number of class files
     * for JDK 11.
     */
    public static final int JAVA_11 = 55;

    
The major version number of class files created
from scratch.  The default value is 47 (JDK 1.3).
It is 49 (JDK 1.5)
if the JVM supports java.lang.StringBuilder.
It is 50 (JDK 1.6)
if the JVM supports java.util.zip.DeflaterInputStream.
It is 51 (JDK 1.7)
if the JVM supports java.lang.invoke.CallSite.
It is 52 (JDK 1.8)
if the JVM supports java.util.function.Function.
It is 53 (JDK 1.9)
if the JVM supports java.lang.reflect.Module.
It is 54 (JDK 10)
if the JVM supports java.util.List.copyOf(Collection).
It is 55 (JDK 11)
if the JVM supports java.util.Optional.isEmpty().

/**
     * The major version number of class files created
     * from scratch.  The default value is 47 (JDK 1.3).
     * It is 49 (JDK 1.5)
     * if the JVM supports <code>java.lang.StringBuilder</code>.
     * It is 50 (JDK 1.6)
     * if the JVM supports <code>java.util.zip.DeflaterInputStream</code>.
     * It is 51 (JDK 1.7)
     * if the JVM supports <code>java.lang.invoke.CallSite</code>.
     * It is 52 (JDK 1.8)
     * if the JVM supports <code>java.util.function.Function</code>.
     * It is 53 (JDK 1.9)
     * if the JVM supports <code>java.lang.reflect.Module</code>.
     * It is 54 (JDK 10)
     * if the JVM supports <code>java.util.List.copyOf(Collection)</code>.
     * It is 55 (JDK 11)
     * if the JVM supports <code>java.util.Optional.isEmpty()</code>.
     */
    public static final int MAJOR_VERSION;

    static {
        int ver = JAVA_3;
        try {
            Class.forName("java.lang.StringBuilder");
            ver = JAVA_5;
            Class.forName("java.util.zip.DeflaterInputStream");
            ver = JAVA_6;
            Class.forName("java.lang.invoke.CallSite", false, ClassLoader.getSystemClassLoader());
            ver = JAVA_7;
            Class.forName("java.util.function.Function");
            ver = JAVA_8;
            Class.forName("java.lang.Module");
            ver = JAVA_9;
            List.class.getMethod("copyOf", Collection.class);
            ver = JAVA_10;
            Class.forName("java.util.Optional").getMethod("isEmpty");
            ver = JAVA_11;
        }
        catch (Throwable t) {}
        MAJOR_VERSION = ver;
    }

    
Constructs a class file from a byte stream.

/**
     * Constructs a class file from a byte stream.
     */
    public ClassFile(DataInputStream in) throws IOException {
        read(in);
    }

    
Constructs a class file including no members.

Params:
  • isInterface – 
           true if this is an interface. false if this is a class.
  • classname – 
           a fully-qualified class name
  • superclass – 
           a fully-qualified super class name or null.
/**
     * Constructs a class file including no members.
     * 
     * @param isInterface
     *            true if this is an interface. false if this is a class.
     * @param classname
     *            a fully-qualified class name
     * @param superclass
     *            a fully-qualified super class name or null.
     */
    public ClassFile(boolean isInterface, String classname, String superclass) {
        major = MAJOR_VERSION;
        minor = 0; // JDK 1.3 or later
        constPool = new ConstPool(classname);
        thisClass = constPool.getThisClassInfo();
        if (isInterface)
            accessFlags = AccessFlag.INTERFACE | AccessFlag.ABSTRACT;
        else
            accessFlags = AccessFlag.SUPER;

        initSuperclass(superclass);
        interfaces = null;
        fields = new ArrayList<FieldInfo>();
        methods = new ArrayList<MethodInfo>();
        thisclassname = classname;

        attributes = new ArrayList<AttributeInfo>();
        attributes.add(new SourceFileAttribute(constPool,
                getSourcefileName(thisclassname)));
    }

    private void initSuperclass(String superclass) {
        if (superclass != null) {
            this.superClass = constPool.addClassInfo(superclass);
            cachedSuperclass = superclass;
        }
        else {
            this.superClass = constPool.addClassInfo("java.lang.Object");
            cachedSuperclass = "java.lang.Object";
        }
    }

    private static String getSourcefileName(String qname) {
        return qname.replaceAll("^.*\\.","") + ".java";
    }

    
Eliminates dead constant pool items. If a method or a field is removed,
the constant pool items used by that method/field become dead items. This
method recreates a constant pool.

/**
     * Eliminates dead constant pool items. If a method or a field is removed,
     * the constant pool items used by that method/field become dead items. This
     * method recreates a constant pool.
     */
    public void compact() {
        ConstPool cp = compact0();
        for (MethodInfo minfo:methods)
            minfo.compact(cp);

        for (FieldInfo finfo:fields)
            finfo.compact(cp);

        attributes = AttributeInfo.copyAll(attributes, cp);
        constPool = cp;
    }

    private ConstPool compact0() {
        ConstPool cp = new ConstPool(thisclassname);
        thisClass = cp.getThisClassInfo();
        String sc = getSuperclass();
        if (sc != null)
            superClass = cp.addClassInfo(getSuperclass());

        if (interfaces != null)
            for (int i = 0; i < interfaces.length; ++i)
                interfaces[i]
                    = cp.addClassInfo(constPool.getClassInfo(interfaces[i]));

        return cp;
    }

    
Discards all attributes, associated with both the class file and the
members such as a code attribute and exceptions attribute. The unused
constant pool entries are also discarded (a new packed constant pool is
constructed).

/**
     * Discards all attributes, associated with both the class file and the
     * members such as a code attribute and exceptions attribute. The unused
     * constant pool entries are also discarded (a new packed constant pool is
     * constructed).
     */
    public void prune() {
        ConstPool cp = compact0();
        List<AttributeInfo> newAttributes = new ArrayList<AttributeInfo>();
        AttributeInfo invisibleAnnotations
            = getAttribute(AnnotationsAttribute.invisibleTag);
        if (invisibleAnnotations != null) {
            invisibleAnnotations = invisibleAnnotations.copy(cp, null);
            newAttributes.add(invisibleAnnotations);
        }

        AttributeInfo visibleAnnotations
            = getAttribute(AnnotationsAttribute.visibleTag);
        if (visibleAnnotations != null) {
            visibleAnnotations = visibleAnnotations.copy(cp, null);
            newAttributes.add(visibleAnnotations);
        }

        AttributeInfo signature
            = getAttribute(SignatureAttribute.tag);
        if (signature != null) {
            signature = signature.copy(cp, null);
            newAttributes.add(signature);
        }

        for (MethodInfo minfo:methods)
            minfo.prune(cp);

        for (FieldInfo finfo:fields)
            finfo.prune(cp);

        attributes = newAttributes;
        constPool = cp;
    }

    
Returns a constant pool table.

/**
     * Returns a constant pool table.
     */
    public ConstPool getConstPool() {
        return constPool;
    }

    
Returns true if this is an interface.

/**
     * Returns true if this is an interface.
     */
    public boolean isInterface() {
        return (accessFlags & AccessFlag.INTERFACE) != 0;
    }

    
Returns true if this is a final class or interface.

/**
     * Returns true if this is a final class or interface.
     */
    public boolean isFinal() {
        return (accessFlags & AccessFlag.FINAL) != 0;
    }

    
Returns true if this is an abstract class or an interface.

/**
     * Returns true if this is an abstract class or an interface.
     */
    public boolean isAbstract() {
        return (accessFlags & AccessFlag.ABSTRACT) != 0;
    }

    
Returns access flags.

See Also:
  • AccessFlag
/**
     * Returns access flags.
     * 
     * @see javassist.bytecode.AccessFlag
     */
    public int getAccessFlags() {
        return accessFlags;
    }

    
Changes access flags.

See Also:
  • AccessFlag
/**
     * Changes access flags.
     * 
     * @see javassist.bytecode.AccessFlag
     */
    public void setAccessFlags(int acc) {
        if ((acc & AccessFlag.INTERFACE) == 0)
            acc |= AccessFlag.SUPER;

        accessFlags = acc;
    }

    
Returns access and property flags of this nested class.
This method returns -1 if the class is not a nested class. 

The returned value is obtained from inner_class_access_flags
of the entry representing this nested class itself
in InnerClasses_attribute. 

/**
     * Returns access and property flags of this nested class.
     * This method returns -1 if the class is not a nested class. 
     *
     * <p>The returned value is obtained from <code>inner_class_access_flags</code>
     * of the entry representing this nested class itself
     * in <code>InnerClasses_attribute</code>. 
     */
    public int getInnerAccessFlags() {
        InnerClassesAttribute ica
            = (InnerClassesAttribute)getAttribute(InnerClassesAttribute.tag);
        if (ica == null)
            return -1;

        String name = getName();
        int n = ica.tableLength();
        for (int i = 0; i < n; ++i)
            if (name.equals(ica.innerClass(i)))
                return ica.accessFlags(i);

        return -1;
    }

    
Returns the class name.

/**
     * Returns the class name.
     */
    public String getName() {
        return thisclassname;
    }

    
Sets the class name. This method substitutes the new name for all
occurrences of the old class name in the class file.

/**
     * Sets the class name. This method substitutes the new name for all
     * occurrences of the old class name in the class file.
     */
    public void setName(String name) {
        renameClass(thisclassname, name);
    }

    
Returns the super class name.

/**
     * Returns the super class name.
     */
    public String getSuperclass() {
        if (cachedSuperclass == null)
            cachedSuperclass = constPool.getClassInfo(superClass);

        return cachedSuperclass;
    }

    
Returns the index of the constant pool entry representing the super
class.

/**
     * Returns the index of the constant pool entry representing the super
     * class.
     */
    public int getSuperclassId() {
        return superClass;
    }

    
Sets the super class.


The new super class should inherit from the old super class.
This method modifies constructors so that they call constructors declared
in the new super class.

/**
     * Sets the super class.
     * 
     * <p>
     * The new super class should inherit from the old super class.
     * This method modifies constructors so that they call constructors declared
     * in the new super class.
     */
    public void setSuperclass(String superclass) throws CannotCompileException {
        if (superclass == null)
            superclass = "java.lang.Object";

        try {
            this.superClass = constPool.addClassInfo(superclass);
            for (MethodInfo minfo:methods)
                minfo.setSuperclass(superclass);
        }
        catch (BadBytecode e) {
            throw new CannotCompileException(e);
        }
        cachedSuperclass = superclass;
    }

    
Replaces all occurrences of a class name in the class file.


If class X is substituted for class Y in the class file, X and Y must
have the same signature. If Y provides a method m(), X must provide it
even if X inherits m() from the super class. If this fact is not
guaranteed, the bytecode verifier may cause an error.

Params:
  • oldname – 
           the replaced class name
  • newname – 
           the substituted class name
/**
     * Replaces all occurrences of a class name in the class file.
     * 
     * <p>
     * If class X is substituted for class Y in the class file, X and Y must
     * have the same signature. If Y provides a method m(), X must provide it
     * even if X inherits m() from the super class. If this fact is not
     * guaranteed, the bytecode verifier may cause an error.
     * 
     * @param oldname
     *            the replaced class name
     * @param newname
     *            the substituted class name
     */
    public final void renameClass(String oldname, String newname) {
        if (oldname.equals(newname))
            return;

        if (oldname.equals(thisclassname))
            thisclassname = newname;

        oldname = Descriptor.toJvmName(oldname);
        newname = Descriptor.toJvmName(newname);
        constPool.renameClass(oldname, newname);

        AttributeInfo.renameClass(attributes, oldname, newname);
        for (MethodInfo minfo :methods) {
            String desc = minfo.getDescriptor();
            minfo.setDescriptor(Descriptor.rename(desc, oldname, newname));
            AttributeInfo.renameClass(minfo.getAttributes(), oldname, newname);
        }

        for (FieldInfo finfo:fields) {
            String desc = finfo.getDescriptor();
            finfo.setDescriptor(Descriptor.rename(desc, oldname, newname));
            AttributeInfo.renameClass(finfo.getAttributes(), oldname, newname);
        }
    }

    
Replaces all occurrences of several class names in the class file.

Params:
  • classnames – 
           specifies which class name is replaced with which new name.
           Class names must be described with the JVM-internal
           representation like java/lang/Object.
See Also:
/**
     * Replaces all occurrences of several class names in the class file.
     * 
     * @param classnames
     *            specifies which class name is replaced with which new name.
     *            Class names must be described with the JVM-internal
     *            representation like <code>java/lang/Object</code>.
     * @see #renameClass(String,String)
     */
    public final void renameClass(Map<String,String> classnames) {
        String jvmNewThisName = classnames.get(Descriptor
                .toJvmName(thisclassname));
        if (jvmNewThisName != null)
            thisclassname = Descriptor.toJavaName(jvmNewThisName);

        constPool.renameClass(classnames);

        AttributeInfo.renameClass(attributes, classnames);
        for (MethodInfo minfo:methods) {
            String desc = minfo.getDescriptor();
            minfo.setDescriptor(Descriptor.rename(desc, classnames));
            AttributeInfo.renameClass(minfo.getAttributes(), classnames);
        }

        for (FieldInfo finfo:fields) {
            String desc = finfo.getDescriptor();
            finfo.setDescriptor(Descriptor.rename(desc, classnames));
            AttributeInfo.renameClass(finfo.getAttributes(), classnames);
        }
    }

    
Internal-use only.
CtClass.getRefClasses() calls this method. 

/**
     * Internal-use only.
     * <code>CtClass.getRefClasses()</code> calls this method. 
     */
    public final void getRefClasses(Map<String,String> classnames) {
        constPool.renameClass(classnames);

        AttributeInfo.getRefClasses(attributes, classnames);
        for (MethodInfo minfo:methods) {
            String desc = minfo.getDescriptor();
            Descriptor.rename(desc, classnames);
            AttributeInfo.getRefClasses(minfo.getAttributes(), classnames);
        }

        for (FieldInfo finfo:fields) {
            String desc = finfo.getDescriptor();
            Descriptor.rename(desc, classnames);
            AttributeInfo.getRefClasses(finfo.getAttributes(), classnames);
        }
    }

    
Returns the names of the interfaces implemented by the class.
The returned array is read only.

/**
     * Returns the names of the interfaces implemented by the class.
     * The returned array is read only.
     */
    public String[] getInterfaces() {
        if (cachedInterfaces != null)
            return cachedInterfaces;

        String[] rtn = null;
        if (interfaces == null)
            rtn = new String[0];
        else {
            String[] list = new String[interfaces.length];
            for (int i = 0; i < interfaces.length; ++i)
                list[i] = constPool.getClassInfo(interfaces[i]);

            rtn = list;
        }

        cachedInterfaces = rtn;
        return rtn;
    }

    
Sets the interfaces.

Params:
  • nameList – 
           the names of the interfaces.
/**
     * Sets the interfaces.
     * 
     * @param nameList
     *            the names of the interfaces.
     */
    public void setInterfaces(String[] nameList) {
        cachedInterfaces = null;
        if (nameList != null) {
            interfaces = new int[nameList.length];
            for (int i = 0; i < nameList.length; ++i)
                interfaces[i] = constPool.addClassInfo(nameList[i]);
        }
    }

    
Appends an interface to the interfaces implemented by the class.

/**
     * Appends an interface to the interfaces implemented by the class.
     */
    public void addInterface(String name) {
        cachedInterfaces = null;
        int info = constPool.addClassInfo(name);
        if (interfaces == null) {
            interfaces = new int[1];
            interfaces[0] = info;
        }
        else {
            int n = interfaces.length;
            int[] newarray = new int[n + 1];
            System.arraycopy(interfaces, 0, newarray, 0, n);
            newarray[n] = info;
            interfaces = newarray;
        }
    }

    
Returns all the fields declared in the class.

See Also:
Returns:a list of FieldInfo.
/**
     * Returns all the fields declared in the class.
     * 
     * @return a list of <code>FieldInfo</code>.
     * @see FieldInfo
     */
    public List<FieldInfo> getFields() {
        return fields;
    }

    
Appends a field to the class.

Throws:
  • DuplicateMemberException –         when the field is already included.
/**
     * Appends a field to the class.
     *
     * @throws DuplicateMemberException         when the field is already included.
     */
    public void addField(FieldInfo finfo) throws DuplicateMemberException {
        testExistingField(finfo.getName(), finfo.getDescriptor());
        fields.add(finfo);
    }

    
Just appends a field to the class.
It does not check field duplication.
Use this method only when minimizing performance overheads
is seriously required.

Since:3.13
/**
     * Just appends a field to the class.
     * It does not check field duplication.
     * Use this method only when minimizing performance overheads
     * is seriously required.
     *
     * @since 3.13
     */
    public final void addField2(FieldInfo finfo) {
        fields.add(finfo);
    }

    private void testExistingField(String name, String descriptor)
            throws DuplicateMemberException {
        for (FieldInfo minfo:fields)
            if (minfo.getName().equals(name))
                throw new DuplicateMemberException("duplicate field: " + name);
    }

    
Returns all the methods declared in the class.

See Also:
Returns:a list of MethodInfo.
/**
     * Returns all the methods declared in the class.
     * 
     * @return a list of <code>MethodInfo</code>.
     * @see MethodInfo
     */
    public List<MethodInfo> getMethods() {
        return methods;
    }

    
Returns the method with the specified name. If there are multiple methods
with that name, this method returns one of them.

Returns:null if no such method is found.
/**
     * Returns the method with the specified name. If there are multiple methods
     * with that name, this method returns one of them.
     * 
     * @return null if no such method is found.
     */
    public MethodInfo getMethod(String name) {
        for (MethodInfo minfo:methods)
            if (minfo.getName().equals(name))
                return minfo;
        return null;
    }

    
Returns a static initializer (class initializer), or null if it does not
exist.

/**
     * Returns a static initializer (class initializer), or null if it does not
     * exist.
     */
    public MethodInfo getStaticInitializer() {
        return getMethod(MethodInfo.nameClinit);
    }

    
Appends a method to the class.
If there is a bridge method with the same name and signature,
then the bridge method is removed before a new method is added.

Throws:
  • DuplicateMemberException –         when the method is already included.
/**
     * Appends a method to the class.
     * If there is a bridge method with the same name and signature,
     * then the bridge method is removed before a new method is added.
     *
     * @throws DuplicateMemberException         when the method is already included.
     */
    public void addMethod(MethodInfo minfo) throws DuplicateMemberException {
        testExistingMethod(minfo);
        methods.add(minfo);
    }

    
Just appends a method to the class.
It does not check method duplication or remove a bridge method.
Use this method only when minimizing performance overheads
is seriously required.

Since:3.13
/**
     * Just appends a method to the class.
     * It does not check method duplication or remove a bridge method.
     * Use this method only when minimizing performance overheads
     * is seriously required.
     *
     * @since 3.13
     */
    public final void addMethod2(MethodInfo minfo) {
        methods.add(minfo);
    }

    private void testExistingMethod(MethodInfo newMinfo)
        throws DuplicateMemberException
    {
        String name = newMinfo.getName();
        String descriptor = newMinfo.getDescriptor();
        ListIterator<MethodInfo> it = methods.listIterator(0);
        while (it.hasNext())
            if (isDuplicated(newMinfo, name, descriptor, it.next(), it))
                throw new DuplicateMemberException("duplicate method: " + name
                                                   + " in " + this.getName());
    }

    private static boolean isDuplicated(MethodInfo newMethod, String newName,
                                        String newDesc, MethodInfo minfo,
                                        ListIterator<MethodInfo> it)
    {
        if (!minfo.getName().equals(newName))
            return false;

        String desc = minfo.getDescriptor();
        if (!Descriptor.eqParamTypes(desc, newDesc))
           return false;

        if (desc.equals(newDesc)) {
            if (notBridgeMethod(minfo))
                return true;
            	// if the bridge method with the same signature
            	// already exists, replace it.
            it.remove();
            return false;
        }
        	return false;
           // return notBridgeMethod(minfo) && notBridgeMethod(newMethod);
    }

    /* For a bridge method, see Sec. 15.12.4.5 of JLS 3rd Ed.
     */
    private static boolean notBridgeMethod(MethodInfo minfo) {
        return (minfo.getAccessFlags() & AccessFlag.BRIDGE) == 0;
    }

    
Returns all the attributes.  The returned List object
is shared with this object.  If you add a new attribute to the list,
the attribute is also added to the classs file represented by this
object.  If you remove an attribute from the list, it is also removed
from the class file.

See Also:
Returns:a list of AttributeInfo objects.
/**
     * Returns all the attributes.  The returned <code>List</code> object
     * is shared with this object.  If you add a new attribute to the list,
     * the attribute is also added to the classs file represented by this
     * object.  If you remove an attribute from the list, it is also removed
     * from the class file.
     * 
     * @return a list of <code>AttributeInfo</code> objects.
     * @see AttributeInfo
     */
    public List<AttributeInfo> getAttributes() {
        return attributes;
    }

    
Returns the attribute with the specified name.  If there are multiple
attributes with that name, this method returns either of them.   It
returns null if the specified attributed is not found.

An attribute name can be obtained by, for example, AnnotationsAttribute.visibleTag or AnnotationsAttribute.invisibleTag. 


Params:
  • name –          attribute name
See Also:
/**
     * Returns the attribute with the specified name.  If there are multiple
     * attributes with that name, this method returns either of them.   It
     * returns null if the specified attributed is not found.
     *
     * <p>An attribute name can be obtained by, for example,
     * {@link AnnotationsAttribute#visibleTag} or
     * {@link AnnotationsAttribute#invisibleTag}. 
     * </p>
     *
     * @param name          attribute name
     * @see #getAttributes()
     */
    public AttributeInfo getAttribute(String name) {
        for (AttributeInfo ai:attributes)
            if (ai.getName().equals(name))
                return ai;
        return null;
    }

    
Removes an attribute with the specified name.

Params:
  • name –      attribute name.
Returns:         the removed attribute or null.
Since:3.21
/**
     * Removes an attribute with the specified name.
     *
     * @param name      attribute name.
     * @return          the removed attribute or null.
     * @since 3.21
     */
    public AttributeInfo removeAttribute(String name) {
        return AttributeInfo.remove(attributes, name);
    }

    
Appends an attribute. If there is already an attribute with the same
name, the new one substitutes for it.

See Also:
  • getAttributes()
/**
     * Appends an attribute. If there is already an attribute with the same
     * name, the new one substitutes for it.
     *
     * @see #getAttributes()
     */
    public void addAttribute(AttributeInfo info) {
        AttributeInfo.remove(attributes, info.getName());
        attributes.add(info);
    }

    
Returns the source file containing this class.

Returns:null if this information is not available.
/**
     * Returns the source file containing this class.
     * 
     * @return null if this information is not available.
     */
    public String getSourceFile() {
        SourceFileAttribute sf
            = (SourceFileAttribute)getAttribute(SourceFileAttribute.tag);
        if (sf == null)
            return null;
        return sf.getFileName();
    }

    private void read(DataInputStream in) throws IOException {
        int i, n;
        int magic = in.readInt();
        if (magic != 0xCAFEBABE)
            throw new IOException("bad magic number: " + Integer.toHexString(magic));

        minor = in.readUnsignedShort();
        major = in.readUnsignedShort();
        constPool = new ConstPool(in);
        accessFlags = in.readUnsignedShort();
        thisClass = in.readUnsignedShort();
        constPool.setThisClassInfo(thisClass);
        superClass = in.readUnsignedShort();
        n = in.readUnsignedShort();
        if (n == 0)
            interfaces = null;
        else {
            interfaces = new int[n];
            for (i = 0; i < n; ++i)
                interfaces[i] = in.readUnsignedShort();
        }

        ConstPool cp = constPool;
        n = in.readUnsignedShort();
        fields = new ArrayList<FieldInfo>();
        for (i = 0; i < n; ++i)
            addField2(new FieldInfo(cp, in));

        n = in.readUnsignedShort();
        methods = new ArrayList<MethodInfo>();
        for (i = 0; i < n; ++i)
            addMethod2(new MethodInfo(cp, in));

        attributes = new ArrayList<AttributeInfo>();
        n = in.readUnsignedShort();
        for (i = 0; i < n; ++i)
            addAttribute(AttributeInfo.read(cp, in));

        thisclassname = constPool.getClassInfo(thisClass);
    }

    
Writes a class file represented by this object into an output stream.

/**
     * Writes a class file represented by this object into an output stream.
     */
    public void write(DataOutputStream out) throws IOException {
        int i, n;

        out.writeInt(0xCAFEBABE); // magic
        out.writeShort(minor); // minor version
        out.writeShort(major); // major version
        constPool.write(out); // constant pool
        out.writeShort(accessFlags);
        out.writeShort(thisClass);
        out.writeShort(superClass);

        if (interfaces == null)
            n = 0;
        else
            n = interfaces.length;

        out.writeShort(n);
        for (i = 0; i < n; ++i)
            out.writeShort(interfaces[i]);

        n = fields.size();
        out.writeShort(n);
        for (i = 0; i < n; ++i) {
            FieldInfo finfo = fields.get(i);
            finfo.write(out);
        }

        out.writeShort(methods.size());
        for (MethodInfo minfo:methods)
            minfo.write(out);

        out.writeShort(attributes.size());
        AttributeInfo.writeAll(attributes, out);
    }

    
Get the Major version.

Returns:the major version
/**
     * Get the Major version.
     * 
     * @return the major version
     */
    public int getMajorVersion() {
        return major;
    }

    
Set the major version.

Params:
  • major – 
           the major version
/**
     * Set the major version.
     * 
     * @param major
     *            the major version
     */
    public void setMajorVersion(int major) {
        this.major = major;
    }

    
Get the minor version.

Returns:the minor version
/**
     * Get the minor version.
     * 
     * @return the minor version
     */
    public int getMinorVersion() {
        return minor;
    }

    
Set the minor version.

Params:
  • minor – 
           the minor version
/**
     * Set the minor version.
     * 
     * @param minor
     *            the minor version
     */
    public void setMinorVersion(int minor) {
        this.minor = minor;
    }

    
Sets the major and minor version to Java 5.
If the major version is older than 49, Java 5
extensions such as annotations are ignored
by the JVM.

/**
     * Sets the major and minor version to Java 5.
     *
     * If the major version is older than 49, Java 5
     * extensions such as annotations are ignored
     * by the JVM.
     */
    public void setVersionToJava5() {
        this.major = 49;
        this.minor = 0;
    }
}