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/InstantiationException.java

/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.lang;

/**
 * Thrown when an application tries to create an instance of a class
 * using the {@code newInstance} method in class
 * {@code Class}, but the specified class object cannot be
 * instantiated.  The instantiation can fail for a variety of
 * reasons including but not limited to:
 *
 * <ul>
 * <li> the class object represents an abstract class, an interface,
 *      an array class, a primitive type, or {@code void}
 * <li> the class has no nullary constructor
 *</ul>
 *
 * @author  unascribed
 * @see     java.lang.Class#newInstance()
 * @since   JDK1.0
 */
public
class InstantiationException extends ReflectiveOperationException {
    private static final long serialVersionUID = -8441929162975509110L;

    /**
     * Constructs an {@code InstantiationException} with no detail message.
     */
    public InstantiationException() {
        super();
    }

    /**
     * Constructs an {@code InstantiationException} with the
     * specified detail message.
     *
     * @param   s   the detail message.
     */
    public InstantiationException(String s) {
        super(s);
    }
}

⏎ java/lang/InstantiationException.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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