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/imageio/spi/OutputStreamImageOutputStreamSpi.java

/*
 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package com.sun.imageio.spi;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Locale;
import javax.imageio.spi.ImageOutputStreamSpi;
import javax.imageio.stream.ImageOutputStream;
import javax.imageio.stream.FileCacheImageOutputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;

public class OutputStreamImageOutputStreamSpi extends ImageOutputStreamSpi {

    private static final String vendorName = "Oracle Corporation";

    private static final String version = "1.0";

    private static final Class outputClass = OutputStream.class;

    public OutputStreamImageOutputStreamSpi() {
        super(vendorName, version, outputClass);
    }

    public String getDescription(Locale locale) {
        return "Service provider that instantiates an OutputStreamImageOutputStream from an OutputStream";
    }

    public boolean canUseCacheFile() {
        return true;
    }

    public boolean needsCacheFile() {
        return false;
    }

    public ImageOutputStream createOutputStreamInstance(Object output,
                                                        boolean useCache,
                                                        File cacheDir)
        throws IOException {
        if (output instanceof OutputStream) {
            OutputStream os = (OutputStream)output;
            if (useCache) {
                return new FileCacheImageOutputStream(os, cacheDir);
            } else {
                return new MemoryCacheImageOutputStream(os);
            }
        } else {
            throw new IllegalArgumentException();
        }
    }
}

⏎ com/sun/imageio/spi/OutputStreamImageOutputStreamSpi.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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