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/area/inline/InlineBlockParent.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: InlineBlockParent.java 1610839 2014-07-15 20:25:58Z vhennebert $ */

package org.apache.fop.area.inline;

import org.apache.fop.area.Area;
import org.apache.fop.area.Block;


/**
 * Inline block parent area.
 * This is an inline area that can have one block area as a child
 */
public class InlineBlockParent extends InlineArea {


    private static final long serialVersionUID = -3661746143321407377L;

    /**
     * The list of inline areas added to this inline parent.
     */
    protected Block child;

    /**
     * Create a new inline block parent to add areas to.
     */
    public InlineBlockParent() {
    }

    /**
     * Override generic Area method.
     *
     * @param childArea the child area to add
     */
    @Override
    public void addChildArea(Area childArea) {
        if (child != null) {
            throw new IllegalStateException("InlineBlockParent may have only one child area.");
        }
        if (childArea instanceof Block) {
            child = (Block) childArea;
            //Update extents from the child
            setIPD(childArea.getAllocIPD());
            setBPD(childArea.getAllocBPD());
        } else {
            throw new IllegalArgumentException("The child of an InlineBlockParent must be a"
                    + " Block area");
        }
    }

    /**
     * Get the child areas for this inline parent.
     *
     * @return the list of child areas
     */
    public Block getChildArea() {
        return child;
    }

}

⏎ org/apache/fop/area/inline/InlineBlockParent.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)