JDK 1.1 source code directory contains Java source code for JDK 1.1 core classes: "C:\fyicenter\jdk-1.1.8\src".

Here is the list of Java classes of the JDK 1.1 source code:

⏎ java/lang/UnknownError.java

/*
 * @(#)UnknownError.java	1.7 01/12/10
 *
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.lang;

/**
 * Thrown when an unknown but serious exception has occurred in the 
 * Java Virtual Machine. 
 *
 * @author unascribed
 * @version 1.7, 12/10/01
 * @since   JDK1.0
 */
public
class UnknownError extends VirtualMachineError {
    /**
     * Constructs an <code>UnknownError</code> with no detail message. 
     *
     * @since   JDK1.0
     */
    public UnknownError() {
	super();
    }

    /**
     * Constructs an <code>UnknownError</code> with the specified detail 
     * message. 
     *
     * @param   s   the detail message.
     * @since   JDK1.0
     */
    public UnknownError(String s) {
	super(s);
    }
}

⏎ java/lang/UnknownError.java

Or download all of them as a single archive file:

File name: jdk-1.1.8-src.zip
File size: 1574187 bytes
Release date: 2018-11-16
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