JRE 8 rt.jar is the JAR file for JRE 8 RT (Runtime) libraries. JRE (Java Runtime) 8 is the runtime environment included in JDK 8. JRE 8 rt.jar libraries are divided into 6 packages:

com.* - Internal Oracle and Sun Microsystems libraries
java.* - Standard Java API libraries.
javax.* - Extended Java API libraries.
jdk.* -  JDK supporting libraries.
org.* - Third party libraries.
sun.* - Old libraries developed by Sun Microsystems.

JAR File Information:

Directory of C:\fyicenter\jdk-1.8.0_191\jre\lib
      63,596,151 rt.jar

Here is the list of Java classes of the javax.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ javax/print/event/PrintJobAttributeEvent.java

/*
 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.print.event;

import javax.print.DocPrintJob;
import javax.print.attribute.AttributeSetUtilities;
import javax.print.attribute.PrintJobAttributeSet;

/**
 * Class PrintJobAttributeEvent encapsulates an event a PrintService
 * reports to let the client know that one or more printing attributes for a
 * PrintJob have changed.
 */

public class PrintJobAttributeEvent extends PrintEvent {

    private static final long serialVersionUID = -6534469883874742101L;

    private PrintJobAttributeSet attributes;

    /**
     * Constructs a PrintJobAttributeEvent object.
     * @param source the print job generating  this event
     * @param attributes the attribute changes being reported
     * @throws IllegalArgumentException if <code>source</code> is
     *         <code>null</code>.
     */
    public PrintJobAttributeEvent (DocPrintJob source,
                                   PrintJobAttributeSet attributes)  {
        super(source);

        this.attributes = AttributeSetUtilities.unmodifiableView(attributes);
    }


    /**
     * Determine the Print Job to which this print job event pertains.
     *
     * @return  Print Job object.
     */
    public DocPrintJob getPrintJob() {

        return (DocPrintJob) getSource();
    }


    /**
     * Determine the printing attributes that changed and their new values.
     *
     * @return  Attributes containing the new values for the print job
     * attributes that changed. The returned set may not be modifiable.
     */
    public PrintJobAttributeSet getAttributes() {

        return attributes;

    }

}

⏎ javax/print/event/PrintJobAttributeEvent.java

Or download all of them as a single archive file:

File name: jre-rt-javax-1.8.0_191-src.zip
File size: 5381005 bytes
Release date: 2018-10-28
Download 

⇒ JRE 8 rt.jar - org.* Package Source Code

⇐ JRE 8 rt.jar - java.* Package Source Code

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