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/afp/modca/PageSegment.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: PageSegment.java 1762060 2016-09-23 12:57:46Z ssteiner $ */

package org.apache.fop.afp.modca;

import java.io.IOException;
import java.io.OutputStream;
import java.util.List;

/**
 * A page segment is a MO:DCA-P resource object.  It may be stored in an
 * external resource library or it may be carried in a resource group.
 * Page segments contain any combination of IOCA image objects and
 * GOCA graphics objects.
 */
public class PageSegment extends AbstractNamedAFPObject {

    private List<AbstractAFPObject> objects;

    /**
     * Main constructor
     *
     * @param name the name of this object
     */
    public PageSegment(String name) {
        super(name);
    }

    /**
     * Returns a list of objects contained withing this page segment
     *
     * @return a list of objects contained within this page segment
     */
    public List<AbstractAFPObject> getObjects() {
        if (objects == null) {
            objects = new java.util.ArrayList();
        }
        return objects;
    }

    /**
     * Adds a resource object (image/graphic) to this page segment
     *
     * @param object the resource objec to add to this page segment
     */
    public void addObject(AbstractAFPObject object) {
        getObjects().add(object);
    }

    /** {@inheritDoc} */
    protected void writeStart(OutputStream os) throws IOException {
        byte[] data = new byte[17];
        copySF(data, Type.BEGIN, Category.PAGE_SEGMENT);
        os.write(data);
    }

    /** {@inheritDoc} */
    protected void writeContent(OutputStream os) throws IOException {
        super.writeContent(os);
        writeObjects(objects, os);
    }

    /** {@inheritDoc} */
    protected void writeEnd(OutputStream os) throws IOException {
        byte[] data = new byte[17];
        copySF(data, Type.END, Category.PAGE_SEGMENT);
        os.write(data);
    }

    /** {@inheritDoc} */
    public String toString() {
        return this.name;
    }
}

⏎ org/apache/fop/afp/modca/PageSegment.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)