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/spi/servicecontext/UnknownServiceContext.java

/*
 * Copyright (c) 1999, 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.spi.servicecontext;

import org.omg.CORBA.SystemException;
import org.omg.CORBA_2_3.portable.InputStream;
import org.omg.CORBA_2_3.portable.OutputStream;
import com.sun.corba.se.spi.ior.iiop.GIOPVersion;
import com.sun.corba.se.spi.servicecontext.ServiceContext ;

public class UnknownServiceContext extends ServiceContext {
    public UnknownServiceContext( int id, byte[] data )
    {
        this.id = id ;
        this.data = data ;
    }

    public UnknownServiceContext( int id, InputStream is )
    {
        this.id = id ;

        int len = is.read_long();
        data = new byte[len];
        is.read_octet_array(data,0,len);
    }

    public int getId() { return id ; }

    public void writeData( OutputStream os ) throws SystemException
    {
    }

    public void write( OutputStream os , GIOPVersion gv)
        throws SystemException
    {
        os.write_long( id ) ;
        os.write_long( data.length ) ;
        os.write_octet_array( data, 0, data.length ) ;
    }

    public byte[] getData()
    {
        return data ;
    }

    private int id = -1 ;
    private byte[] data = null ;
}

⏎ com/sun/corba/se/spi/servicecontext/UnknownServiceContext.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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