repeated call of Mixer.open() method throws a NullPointerException

Name: abR10010 Date: 04/18/2002



The specification for the Mixer class from the javax.sound.sampled package
doesn't say that repeated call of Mixer.open() method is not permitted.

However the simple test (see below) shows the Mixer.open()
method throws a NullPointerException for the one of installed on the system
mixers with JDK 1.4.1-beta-b08 when this method is called after the Mixer
is closed.

This bug causes failure of new JCK test:
 api/javax_sound/sampled/Mixer/index.html#open

Please, see test log:

% java -version
java version "1.4.1-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1-beta-b08)
Java HotSpot(TM) Client VM (build 1.4.1-beta-b08, mixed mode)

% java test

==> Test for Mixer.open() method:

>> testedMixer = com.sun.media.sound.HeadspaceMixer@80f4cb
> testedMixer.isOpen() = false
> testedMixer.open() - O'Key
> testedMixer.isOpen() = true
> testedMixer.close() - O'Key
> testedMixer.isOpen() = false
> testedMixer.open() - O'Key
> testedMixer.isOpen() = true
> testedMixer.close() - O'Key
> testedMixer.isOpen() = false

>> testedMixer = com.sun.media.sound.SimpleInputDevice@60420f
> testedMixer.isOpen() = false
> testedMixer.open() - O'Key
> testedMixer.isOpen() = true
> testedMixer.close() - O'Key
> testedMixer.isOpen() = false
> testedMixer.open() - O'Key
> testedMixer.isOpen() = true
> testedMixer.close() - O'Key
> testedMixer.isOpen() = false

>> testedMixer = com.sun.media.sound.SimpleOutputDevice@19106c7
> testedMixer.isOpen() = false
> testedMixer.open() - O'Key
> testedMixer.isOpen() = true
> testedMixer.close() - O'Key
> testedMixer.isOpen() = false
## Mixer.open() threw unexpected exception:
# Mixer = com.sun.media.sound.SimpleOutputDevice@19106c7
java.lang.NullPointerException
at com.sun.media.sound.SimpleOutputDevice.implOpen(SimpleOutputDevice.java:372)
at com.sun.media.sound.AbstractDataLine.open(AbstractDataLine.java:85)
at com.sun.media.sound.AbstractMixer.open(AbstractMixer.java:272)
at com.sun.media.sound.AbstractMixer.open(AbstractMixer.java:288)
at test.run(test.java:77)
at test.main(test.java:13)

==> test FAILED!
 
 
The test source:
------------------------------- test.java --------------------------------
// File: %Z%%M% %I% %E%
// Copyright %G% Sun Microsystems, Inc. All Rights Reserved

import javax.sound.sampled.*;

public class test {

    static final int STATUS_PASSED = 0;
    static final int STATUS_FAILED = 2;
    static final int STATUS_TEMP = 95;
    
    public static void main(String argv[]) {
        int testExitStatus = run(argv, System.out) + STATUS_TEMP;
        System.exit(testExitStatus);
    }

    public static int run(String argv[], java.io.PrintStream out) {
        int testResult = STATUS_PASSED;
    
        out.println("==> Test for Mixer.open() method:");

        Mixer.Info[] installedMixersInfo = AudioSystem.getMixerInfo();
    
        if ( installedMixersInfo == null ) {
            out.println("## AudioSystem.getMixerInfo() returned unexpected result:");
            out.println
                ("# expected: an array of Mixer.Info objects (may be array of length 0);");
            out.println("# produced: null;");
            return STATUS_FAILED;
        }

        if ( installedMixersInfo.length == 0 ) {
            out.println(">> there are no mixers installed on the system");
            return STATUS_PASSED;
        }

        Mixer testedMixer = null;
        for (int i=0; i < installedMixersInfo.length; i++) {
            try {
                testedMixer = AudioSystem.getMixer(installedMixersInfo[i]);
            } catch (SecurityException securityException) {
                // installed Mixer is unavailable because of security restrictions
                continue;
            } catch (Throwable thrown) {
                out.println("## AudioSystem.getMixer() threw unexpected exception:");
                thrown.printStackTrace(out);
                testResult = STATUS_FAILED;
                continue;
            }

            out.println("\n>> testedMixer = " + testedMixer);
        
            out.println("> testedMixer.isOpen() = " + testedMixer.isOpen());
            try {
                testedMixer.open();
                out.println("> testedMixer.open() - O'Key");
            } catch (LineUnavailableException lineUnavailableException) {
                // testedMixer is not available due to resource restrictions
                out.println("> testedMixer is not available due to resource restrictions");
                continue;
            } catch (SecurityException securityException) {
                // testedMixer is not available due to security restrictions
                out.println("> testedMixer is not available due to security restrictions");
                continue;
            } catch (Throwable thrown) {
                out.println("## Mixer.open() threw unexpected exception:");
                out.println("# Mixer = " + testedMixer);
                thrown.printStackTrace(out);
                testResult = STATUS_FAILED;
                continue;
            }
            out.println("> testedMixer.isOpen() = " + testedMixer.isOpen());
            testedMixer.close();
            out.println("> testedMixer.close() - O'Key");

            out.println("> testedMixer.isOpen() = " + testedMixer.isOpen());
            try {
                testedMixer.open();
                out.println("> testedMixer.open() - O'Key");
            } catch (LineUnavailableException lineUnavailableException) {
                // testedMixer is not available due to resource restrictions
                out.println("> testedMixer is not available due to resource restrictions");
                continue;
            } catch (SecurityException securityException) {
                // testedMixer is not available due to security restrictions
                out.println("> testedMixer is not available due to security restrictions");
                continue;
            } catch (Throwable thrown) {
                out.println("## Mixer.open() threw unexpected exception:");
                out.println("# Mixer = " + testedMixer);
                thrown.printStackTrace(out);
                testResult = STATUS_FAILED;
                continue;
            }
            out.println("> testedMixer.isOpen() = " + testedMixer.isOpen());
            testedMixer.close();
            out.println("> testedMixer.close() - O'Key");
            out.println("> testedMixer.isOpen() = " + testedMixer.isOpen());

        } // for (int i=0; i < installedMixersInfo.length; i++)

        if ( testResult == STATUS_FAILED ) {
            out.println("\n==> test FAILED!");
        } else {
            out.println("\n==> test PASSED!");
        }
        return testResult;
    }
} // end of test class
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