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

⏎ javax/lang/model/type/MirroredTypesException.java

/*
 * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.lang.model.type;

import java.util.ArrayList;
import java.util.List;
import java.util.Collections;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.lang.model.element.Element;


/**
 * Thrown when an application attempts to access a sequence of {@link
 * Class} objects each corresponding to a {@link TypeMirror}.
 *
 * @author Joseph D. Darcy
 * @author Scott Seligman
 * @author Peter von der Ahé
 * @see MirroredTypeException
 * @see Element#getAnnotation(Class)
 * @since 1.6
 */
public class MirroredTypesException extends RuntimeException {

    private static final long serialVersionUID = 269;

    transient List<? extends TypeMirror> types; // cannot be serialized

    /*
     * Trusted constructor to be called by MirroredTypeException.
     */
    MirroredTypesException(String message, TypeMirror type) {
        super(message);
        List<TypeMirror> tmp = (new ArrayList<TypeMirror>());
        tmp.add(type);
        types = Collections.unmodifiableList(tmp);
    }

    /**
     * Constructs a new MirroredTypesException for the specified types.
     *
     * @param types  the types being accessed
     */
    public MirroredTypesException(List<? extends TypeMirror> types) {
        super("Attempt to access Class objects for TypeMirrors " +
              (types = // defensive copy
               new ArrayList<TypeMirror>(types)).toString() );
        this.types = Collections.unmodifiableList(types);
    }

    /**
     * Returns the type mirrors corresponding to the types being accessed.
     * The type mirrors may be unavailable if this exception has been
     * serialized and then read back in.
     *
     * @return the type mirrors in construction order, or {@code null} if unavailable
     */
    public List<? extends TypeMirror> getTypeMirrors() {
        return types;
    }

    /**
     * Explicitly set all transient fields.
     */
    private void readObject(ObjectInputStream s)
        throws IOException, ClassNotFoundException {
        s.defaultReadObject();
        types = null;
    }
}

⏎ javax/lang/model/type/MirroredTypesException.java

Or download all of them as a single archive file:

File name: jre-rt-javax-1.8.0_191-src.zip
File size: 5381005 bytes
Release date: 2018-10-28
Download 

⇒ JRE 8 rt.jar - org.* Package Source Code

⇐ JRE 8 rt.jar - java.* Package Source Code

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