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/naming/TimeLimitExceededException.java

/*
 * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.naming;

import javax.naming.Name;

/**
 * This exception is thrown when a method
 * does not terminate within the specified time limit.
 * This can happen, for example, if the user specifies that
 * the method should take no longer than 10 seconds, and the
 * method fails to complete with 10 seconds.
 *
 * <p> Synchronization and serialization issues that apply to NamingException
 * apply directly here.
 *
 * @author Rosanna Lee
 * @author Scott Seligman
 *
 * @since 1.3
 */
public class TimeLimitExceededException extends LimitExceededException {
    /**
     * Constructs a new instance of TimeLimitExceededException.
     * All fields default to null.
     */
    public TimeLimitExceededException() {
        super();
    }

    /**
     * Constructs a new instance of TimeLimitExceededException
     * using the argument supplied.
     * @param explanation possibly null detail about this exception.
     * @see java.lang.Throwable#getMessage
     */
    public TimeLimitExceededException(String explanation) {
        super(explanation);
    }

    /**
     * Use serialVersionUID from JNDI 1.1.1 for interoperability
     */
    private static final long serialVersionUID = -3597009011385034696L;
}

⏎ javax/naming/TimeLimitExceededException.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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