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/auth/callback/PasswordCallback.java

/*
 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package javax.security.auth.callback;

/**
 * <p> Underlying security services instantiate and pass a
 * {@code PasswordCallback} to the {@code handle}
 * method of a {@code CallbackHandler} to retrieve password information.
 *
 * @see javax.security.auth.callback.CallbackHandler
 */
public class PasswordCallback implements Callback, java.io.Serializable {

    private static final long serialVersionUID = 2267422647454909926L;

    /**
     * @serial
     * @since 1.4
     */
    private String prompt;
    /**
     * @serial
     * @since 1.4
     */
    private boolean echoOn;
    /**
     * @serial
     * @since 1.4
     */
    private char[] inputPassword;

    /**
     * Construct a {@code PasswordCallback} with a prompt
     * and a boolean specifying whether the password should be displayed
     * as it is being typed.
     *
     * <p>
     *
     * @param prompt the prompt used to request the password. <p>
     *
     * @param echoOn true if the password should be displayed
     *                  as it is being typed.
     *
     * @exception IllegalArgumentException if {@code prompt} is null or
     *                  if {@code prompt} has a length of 0.
     */
    public PasswordCallback(String prompt, boolean echoOn) {
        if (prompt == null || prompt.length() == 0)
            throw new IllegalArgumentException();

        this.prompt = prompt;
        this.echoOn = echoOn;
    }

    /**
     * Get the prompt.
     *
     * <p>
     *
     * @return the prompt.
     */
    public String getPrompt() {
        return prompt;
    }

    /**
     * Return whether the password
     * should be displayed as it is being typed.
     *
     * <p>
     *
     * @return the whether the password
     *          should be displayed as it is being typed.
     */
    public boolean isEchoOn() {
        return echoOn;
    }

    /**
     * Set the retrieved password.
     *
     * <p> This method makes a copy of the input <i>password</i>
     * before storing it.
     *
     * <p>
     *
     * @param password the retrieved password, which may be null.
     *
     * @see #getPassword
     */
    public void setPassword(char[] password) {
        this.inputPassword = (password == null ? null : password.clone());
    }

    /**
     * Get the retrieved password.
     *
     * <p> This method returns a copy of the retrieved password.
     *
     * <p>
     *
     * @return the retrieved password, which may be null.
     *
     * @see #setPassword
     */
    public char[] getPassword() {
        return (inputPassword == null ? null : inputPassword.clone());
    }

    /**
     * Clear the retrieved password.
     */
    public void clearPassword() {
        if (inputPassword != null) {
            for (int i = 0; i < inputPassword.length; i++)
                inputPassword[i] = ' ';
        }
    }
}

⏎ javax/security/auth/callback/PasswordCallback.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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