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 java.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ java/lang/Error.java

/*
 * Copyright (c) 1995, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.lang;

/**
 * An {@code Error} is a subclass of {@code Throwable}
 * that indicates serious problems that a reasonable application
 * should not try to catch. Most such errors are abnormal conditions.
 * The {@code ThreadDeath} error, though a "normal" condition,
 * is also a subclass of {@code Error} because most applications
 * should not try to catch it.
 * <p>
 * A method is not required to declare in its {@code throws}
 * clause any subclasses of {@code Error} that might be thrown
 * during the execution of the method but not caught, since these
 * errors are abnormal conditions that should never occur.
 *
 * That is, {@code Error} and its subclasses are regarded as unchecked
 * exceptions for the purposes of compile-time checking of exceptions.
 *
 * @author  Frank Yellin
 * @see     java.lang.ThreadDeath
 * @jls 11.2 Compile-Time Checking of Exceptions
 * @since   JDK1.0
 */
public class Error extends Throwable {
    static final long serialVersionUID = 4980196508277280342L;

    /**
     * Constructs a new error with {@code null} as its detail message.
     * The cause is not initialized, and may subsequently be initialized by a
     * call to {@link #initCause}.
     */
    public Error() {
        super();
    }

    /**
     * Constructs a new error with the specified detail message.  The
     * cause is not initialized, and may subsequently be initialized by
     * a call to {@link #initCause}.
     *
     * @param   message   the detail message. The detail message is saved for
     *          later retrieval by the {@link #getMessage()} method.
     */
    public Error(String message) {
        super(message);
    }

    /**
     * Constructs a new error with the specified detail message and
     * cause.  <p>Note that the detail message associated with
     * {@code cause} is <i>not</i> automatically incorporated in
     * this error's detail message.
     *
     * @param  message the detail message (which is saved for later retrieval
     *         by the {@link #getMessage()} method).
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link #getCause()} method).  (A {@code null} value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since  1.4
     */
    public Error(String message, Throwable cause) {
        super(message, cause);
    }

    /**
     * Constructs a new error with the specified cause and a detail
     * message of {@code (cause==null ? null : cause.toString())} (which
     * typically contains the class and detail message of {@code cause}).
     * This constructor is useful for errors that are little more than
     * wrappers for other throwables.
     *
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link #getCause()} method).  (A {@code null} value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since  1.4
     */
    public Error(Throwable cause) {
        super(cause);
    }

    /**
     * Constructs a new error with the specified detail message,
     * cause, suppression enabled or disabled, and writable stack
     * trace enabled or disabled.
     *
     * @param  message the detail message.
     * @param cause the cause.  (A {@code null} value is permitted,
     * and indicates that the cause is nonexistent or unknown.)
     * @param enableSuppression whether or not suppression is enabled
     *                          or disabled
     * @param writableStackTrace whether or not the stack trace should
     *                           be writable
     *
     * @since 1.7
     */
    protected Error(String message, Throwable cause,
                    boolean enableSuppression,
                    boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

⏎ java/lang/Error.java

Or download all of them as a single archive file:

File name: jre-rt-java-1.8.0_191-src.zip
File size: 6664831 bytes
Release date: 2018-10-28
Download 

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