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

⏎ java/security/AlgorithmParameterGeneratorSpi.java

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.security;

import java.security.spec.AlgorithmParameterSpec;

/**
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the {@code AlgorithmParameterGenerator} class, which
 * is used to generate a set of parameters to be used with a certain algorithm.
 *
 * <p> All the abstract methods in this class must be implemented by each
 * cryptographic service provider who wishes to supply the implementation
 * of a parameter generator for a particular algorithm.
 *
 * <p> In case the client does not explicitly initialize the
 * AlgorithmParameterGenerator (via a call to an {@code engineInit}
 * method), each provider must supply (and document) a default initialization.
 * For example, the Sun provider uses a default modulus prime size of 1024
 * bits for the generation of DSA parameters.
 *
 * @author Jan Luehe
 *
 *
 * @see AlgorithmParameterGenerator
 * @see AlgorithmParameters
 * @see java.security.spec.AlgorithmParameterSpec
 *
 * @since 1.2
 */

public abstract class AlgorithmParameterGeneratorSpi {

    /**
     * Initializes this parameter generator for a certain size
     * and source of randomness.
     *
     * @param size the size (number of bits).
     * @param random the source of randomness.
     */
    protected abstract void engineInit(int size, SecureRandom random);

    /**
     * Initializes this parameter generator with a set of
     * algorithm-specific parameter generation values.
     *
     * @param genParamSpec the set of algorithm-specific parameter generation values.
     * @param random the source of randomness.
     *
     * @exception InvalidAlgorithmParameterException if the given parameter
     * generation values are inappropriate for this parameter generator.
     */
    protected abstract void engineInit(AlgorithmParameterSpec genParamSpec,
                                       SecureRandom random)
        throws InvalidAlgorithmParameterException;

    /**
     * Generates the parameters.
     *
     * @return the new AlgorithmParameters object.
     */
    protected abstract AlgorithmParameters engineGenerateParameters();
}

⏎ java/security/AlgorithmParameterGeneratorSpi.java

Or download all of them as a single archive file:

File name: jre-rt-java-1.8.0_191-src.zip
File size: 6664831 bytes
Release date: 2018-10-28
Download 

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