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/verifier/statics/DOUBLE_Upper.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.verifier.statics;


import org.apache.bcel.Const;
import org.apache.bcel.generic.Type;

/**
 * This class represents the upper half of a DOUBLE variable.
 */
public final class DOUBLE_Upper extends Type{

    /** The one and only instance of this class. */
    private static final DOUBLE_Upper singleton = new DOUBLE_Upper();

    /** The constructor; this class must not be instantiated from the outside. */
    private DOUBLE_Upper() {
        super(Const.T_UNKNOWN, "Double_Upper");
    }

    /**
     * Gets the single instance of this class.
     *
     * @return the single instance of this class.
     */
    public static DOUBLE_Upper theInstance() {
        return singleton;
    }
}

⏎ org/apache/bcel/verifier/statics/DOUBLE_Upper.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