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/invoke/LambdaConversionException.java

/*
 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.lang.invoke;

/**
 * LambdaConversionException
 */
public class LambdaConversionException extends Exception {
    private static final long serialVersionUID = 292L + 8L;

    /**
     * Constructs a {@code LambdaConversionException}.
     */
    public LambdaConversionException() {
    }

    /**
     * Constructs a {@code LambdaConversionException} with a message.
     * @param message the detail message
     */
    public LambdaConversionException(String message) {
        super(message);
    }

    /**
     * Constructs a {@code LambdaConversionException} with a message and cause.
     * @param message the detail message
     * @param cause the cause
     */
    public LambdaConversionException(String message, Throwable cause) {
        super(message, cause);
    }

    /**
     * Constructs a {@code LambdaConversionException} with a cause.
     * @param cause the cause
     */
    public LambdaConversionException(Throwable cause) {
        super(cause);
    }

    /**
     * Constructs a {@code LambdaConversionException} with a message,
     * cause, and other settings.
     * @param message the detail message
     * @param cause the cause
     * @param enableSuppression whether or not suppressed exceptions are enabled
     * @param writableStackTrace whether or not the stack trace is writable
     */
    public LambdaConversionException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

⏎ java/lang/invoke/LambdaConversionException.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 

⇒ JRE 8 rt.jar - javax.* Package Source Code

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