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/beans/NameGenerator.java

/*
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package java.beans;

import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.Map;

import static java.util.Locale.ENGLISH;

/**
 * A utility class which generates unique names for object instances.
 * The name will be a concatenation of the unqualified class name
 * and an instance number.
 * <p>
 * For example, if the first object instance javax.swing.JButton
 * is passed into <code>instanceName</code> then the returned
 * string identifier will be &quot;JButton0&quot;.
 *
 * @author Philip Milne
 */
class NameGenerator {

    private Map<Object, String> valueToName;
    private Map<String, Integer> nameToCount;

    public NameGenerator() {
        valueToName = new IdentityHashMap<>();
        nameToCount = new HashMap<>();
    }

    /**
     * Clears the name cache. Should be called to near the end of
     * the encoding cycle.
     */
    public void clear() {
        valueToName.clear();
        nameToCount.clear();
    }

    /**
     * Returns the root name of the class.
     */
    @SuppressWarnings("rawtypes")
    public static String unqualifiedClassName(Class type) {
        if (type.isArray()) {
            return unqualifiedClassName(type.getComponentType())+"Array";
        }
        String name = type.getName();
        return name.substring(name.lastIndexOf('.')+1);
    }

    /**
     * Returns a String which capitalizes the first letter of the string.
     */
    public static String capitalize(String name) {
        if (name == null || name.length() == 0) {
            return name;
        }
        return name.substring(0, 1).toUpperCase(ENGLISH) + name.substring(1);
    }

    /**
     * Returns a unique string which identifies the object instance.
     * Invocations are cached so that if an object has been previously
     * passed into this method then the same identifier is returned.
     *
     * @param instance object used to generate string
     * @return a unique string representing the object
     */
    public String instanceName(Object instance) {
        if (instance == null) {
            return "null";
        }
        if (instance instanceof Class) {
            return unqualifiedClassName((Class)instance);
        }
        else {
            String result = valueToName.get(instance);
            if (result != null) {
                return result;
            }
            Class<?> type = instance.getClass();
            String className = unqualifiedClassName(type);

            Integer size = nameToCount.get(className);
            int instanceNumber = (size == null) ? 0 : (size).intValue() + 1;
            nameToCount.put(className, new Integer(instanceNumber));

            result = className + instanceNumber;
            valueToName.put(instance, result);
            return result;
        }
    }
}

⏎ java/beans/NameGenerator.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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