What Is fop.jar? I got it from the fop-2.7-bin.zip.

fop.jar in fop-2.7-bin.zip is the JAR file for FOP 2.7, which is a print formatter driven by XSL formatting objects (XSL-FO). You can obtain fop.jar from the build folder of the fop-2.7-bin.zip file.

Below is the information about the fop.jar (2.2) file:

JAR File Size and Download Location:

JAR name: fop.jar, fop-2.7.jar
Target JDK version: 1.7
File name: fop.jar
File size: 4442817 bytes
Release date: 20-Jan-2022
Download: Apache FOP Website

Java source code files for fop.jar:

⏎ org/apache/fop/pdf/xref/CompressedObjectReference.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.
 */

/* $Id: CompressedObjectReference.java 1661887 2015-02-24 11:23:44Z ssteiner $ */

package org.apache.fop.pdf.xref;

import java.io.DataOutputStream;
import java.io.IOException;

import org.apache.fop.pdf.PDFObjectNumber;

/**
 * A reference to an indirect object stored in an object stream. Contains the relevant
 * information to add to a cross-reference stream.
 */
public class CompressedObjectReference implements ObjectReference {

    private final PDFObjectNumber objectNumber;

    private final PDFObjectNumber objectStreamNumber;

    private final int index;

    /**
     * Creates a new reference.
     *
     * @param objectNumber the number of the compressed object being referenced
     * @param objectStreamNumber the number of the object stream in which the compressed
     * object is to be found
     * @param index the index of the compressed object in the object stream
     */
    public CompressedObjectReference(PDFObjectNumber objectNumber, PDFObjectNumber objectStreamNumber, int index) {
        this.objectNumber = objectNumber;
        this.objectStreamNumber = objectStreamNumber;
        this.index = index;
    }

    public void output(DataOutputStream out) throws IOException {
        out.write(2);
        out.writeLong(objectStreamNumber.getNumber());
        out.write(0);
        out.write(index);
    }

    public PDFObjectNumber getObjectNumber() {
        return objectNumber;
    }

    public PDFObjectNumber getObjectStreamNumber() {
        return objectStreamNumber;
    }

}

⏎ org/apache/fop/pdf/xref/CompressedObjectReference.java

Or download all of them as a single archive file:

File name: fop-2.7-src.zip
File size: 3401312 bytes
Release date: 2022-01-20
Download 

⇒ "fop" Command in fop-2.7-bin.zip

⇐ What Is fop-2.7-bin.zip

⇑ Download and Installing of FOP 2.x

⇑⇑ FAQ for FOP (Formatting Object Processor)