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/orb/ORBVersionImpl.java

/*
 * Copyright (c) 2000, 2003, 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.orb ;

import org.omg.CORBA.portable.OutputStream ;

import com.sun.corba.se.spi.orb.ORBVersion ;

public class ORBVersionImpl implements ORBVersion {
    private byte orbType ;

    public ORBVersionImpl( byte orbType )
    {
        this.orbType = orbType ;
    }

    public static final ORBVersion FOREIGN = new ORBVersionImpl(
        ORBVersion.FOREIGN ) ;

    public static final ORBVersion OLD = new ORBVersionImpl(
        ORBVersion.OLD ) ;

    public static final ORBVersion NEW = new ORBVersionImpl(
        ORBVersion.NEW ) ;

    public static final ORBVersion JDK1_3_1_01 = new ORBVersionImpl(
        ORBVersion.JDK1_3_1_01 ) ;

    public static final ORBVersion NEWER = new ORBVersionImpl(
        ORBVersion.NEWER ) ;

    public static final ORBVersion PEORB = new ORBVersionImpl(
        ORBVersion.PEORB ) ;

    public byte getORBType()
    {
        return orbType ;
    }

    public void write( OutputStream os )
    {
        os.write_octet( (byte)orbType ) ;
    }

    public String toString()
    {
        return "ORBVersionImpl[" + Byte.toString( orbType ) + "]" ;
    }

    public boolean equals( Object obj )
    {
        if (!(obj instanceof ORBVersion))
            return false ;

        ORBVersion version = (ORBVersion)obj ;
        return version.getORBType() == orbType ;
    }

    public int hashCode()
    {
        return orbType ;
    }

    public boolean lessThan(ORBVersion version) {
        return orbType < version.getORBType();
    }

    public int compareTo(Object obj) {
        // The Comparable interface says that this
        // method throws a ClassCastException if the
        // given object's type prevents it from being
        // compared.
        return getORBType() - ((ORBVersion)obj).getORBType();
    }
}

⏎ com/sun/corba/se/impl/orb/ORBVersionImpl.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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