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

⏎ com/sun/corba/se/impl/orbutil/CorbaResourceUtil.java

/*
 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package com.sun.corba.se.impl.orbutil;

import java.util.ResourceBundle;
import java.util.MissingResourceException;

public class CorbaResourceUtil {
    public static String getString(String key) {
        if (!resourcesInitialized) {
            initResources();
        }

        try {
            return resources.getString(key);
        } catch (MissingResourceException ignore) {
        }
        return null;
    }

    public static String getText(String key) {
        String message = getString(key);
        if (message == null) {
            message = "no text found: \"" + key + "\"";
        }
        return message;
    }

    public static String getText(String key, int num) {
        return getText(key, Integer.toString(num), null, null);
    }

    public static String getText(String key, String arg0) {
        return getText(key, arg0, null, null);
    }

    public static String getText(String key, String arg0, String arg1) {
        return getText(key, arg0, arg1, null);
    }

    public static String getText(String key,
                                 String arg0, String arg1, String arg2)
    {
        String format = getString(key);
        if (format == null) {
            format = "no text found: key = \"" + key + "\", " +
                "arguments = \"{0}\", \"{1}\", \"{2}\"";
        }

        String[] args = new String[3];
        args[0] = (arg0 != null ? arg0.toString() : "null");
        args[1] = (arg1 != null ? arg1.toString() : "null");
        args[2] = (arg2 != null ? arg2.toString() : "null");

        return java.text.MessageFormat.format(format, (Object[]) args);
    }

    private static boolean resourcesInitialized = false;
    private static ResourceBundle resources;

    private static void initResources() {
        try {
            resources =
                ResourceBundle.getBundle("com.sun.corba.se.impl.orbutil.resources.sunorb");
            resourcesInitialized = true;
        } catch (MissingResourceException e) {
            throw new Error("fatal: missing resource bundle: " +
                            e.getClassName());
        }
    }

}

⏎ com/sun/corba/se/impl/orbutil/CorbaResourceUtil.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
Download 

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