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/NameParser.java

/*
 * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.naming;

/**
  * This interface is used for parsing names from a hierarchical
  * namespace.  The NameParser contains knowledge of the syntactic
  * information (like left-to-right orientation, name separator, etc.)
  * needed to parse names.
  *
  * The equals() method, when used to compare two NameParsers, returns
  * true if and only if they serve the same namespace.
  *
  * @author Rosanna Lee
  * @author Scott Seligman
  *
  * @see CompoundName
  * @see Name
  * @since 1.3
  */

public interface NameParser {
        /**
          * Parses a name into its components.
          *
          * @param name The non-null string name to parse.
          * @return A non-null parsed form of the name using the naming convention
          * of this parser.
          * @exception InvalidNameException If name does not conform to
          *     syntax defined for the namespace.
          * @exception NamingException If a naming exception was encountered.
          */
        Name parse(String name) throws NamingException;
}

⏎ javax/naming/NameParser.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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