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/security/sasl/RealmCallback.java

/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package javax.security.sasl;

import javax.security.auth.callback.TextInputCallback;

/**
  * This callback is used by {@code SaslClient} and {@code SaslServer}
  * to retrieve realm information.
  *
  * @since 1.5
  *
  * @author Rosanna Lee
  * @author Rob Weltman
  */
public class RealmCallback extends TextInputCallback {

    /**
     * Constructs a {@code RealmCallback} with a prompt.
     *
     * @param prompt The non-null prompt to use to request the realm information.
     * @throws IllegalArgumentException If {@code prompt} is null or
     * the empty string.
     */
    public RealmCallback(String prompt) {
        super(prompt);
    }

    /**
     * Constructs a {@code RealmCallback} with a prompt and default
     * realm information.
     *
     * @param prompt The non-null prompt to use to request the realm information.
     * @param defaultRealmInfo The non-null default realm information to use.
     * @throws IllegalArgumentException If {@code prompt} is null or
     * the empty string,
     * or if {@code defaultRealm} is empty or null.
     */
    public RealmCallback(String prompt, String defaultRealmInfo) {
        super(prompt, defaultRealmInfo);
    }

    private static final long serialVersionUID = -4342673378785456908L;
}

⏎ javax/security/sasl/RealmCallback.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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