Apache BCEL Source Code Files are inside the Apache BCEL source package file like bcel-6.5.0-src.zip. Unzip the source package file and go to the "src/main" sub-directory, you will see source code files.

Here is the list of Java source code files of the Apache BCEL 6.5.0 in \Users\fyicenter\bcel-6.5.0\src:

⏎ org/apache/bcel/classfile/ConstantInterfaceMethodref.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.bcel.classfile;

import java.io.DataInput;
import java.io.IOException;

import org.apache.bcel.Const;

/**
 * This class represents a constant pool reference to an interface method.
 *
 */
public final class ConstantInterfaceMethodref extends ConstantCP {

    /**
     * Initialize from another object.
     */
    public ConstantInterfaceMethodref(final ConstantInterfaceMethodref c) {
        super(Const.CONSTANT_InterfaceMethodref, c.getClassIndex(), c.getNameAndTypeIndex());
    }


    /**
     * Initialize instance from input data.
     *
     * @param input input stream
     * @throws IOException
     */
    ConstantInterfaceMethodref(final DataInput input) throws IOException {
        super(Const.CONSTANT_InterfaceMethodref, input);
    }


    /**
     * @param class_index Reference to the class containing the method
     * @param name_and_type_index and the method signature
     */
    public ConstantInterfaceMethodref(final int class_index, final int name_and_type_index) {
        super(Const.CONSTANT_InterfaceMethodref, class_index, name_and_type_index);
    }


    /**
     * Called by objects that are traversing the nodes of the tree implicitely
     * defined by the contents of a Java class. I.e., the hierarchy of methods,
     * fields, attributes, etc. spawns a tree of objects.
     *
     * @param v Visitor object
     */
    @Override
    public void accept( final Visitor v ) {
        v.visitConstantInterfaceMethodref(this);
    }
}

⏎ org/apache/bcel/classfile/ConstantInterfaceMethodref.java

Or download all of them as a single archive file:

File name: bcel-6.5.0-fyi.zip
File size: 706792 bytes
Release date: 2020-07-03
Download 

⇒ JDK "javap" Command

⇐ Install Apache BCEL 6.5.0 Binary Package

⇑ Apache BCEL (Byte Code Engineering Library)

⇑⇑ Java Bytecode Tools