Java web start doesn't work after java version

问题:

Our java application is launchend via java web start (with glassfish 4.0). After updating to java 7u45, it doesn't work anymore. Here is the error message:

java.lang.NullPointerException
at java.io.StringReader.<init>(Unknown Source)
at org.glassfish.appclient.client.JWSAppClientContainerMain.insertMaskingLoader(JWSAppClientContainerMain.java:186)
at org.glassfish.appclient.client.JWSAppClientContainerMain.main(JWSAppClientContainerMain.java:132)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javaws.Launcher.executeApplication(Unknown Source)
at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
at com.sun.javaws.Launcher.doLaunchApp(Unknown Source)
at com.sun.javaws.Launcher.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

This happens right after the download finished. After a quick look into the GF source file, it seems that the property loader.config is not defined as the second line throws the NPE:

final String loaderConfig = System.getProperty("loader.config");
StringReader sr = new StringReader(loaderConfig);

EDIT The above two code lines where the NPE happens is Glassfish code, from the Class JWSAppClientContainerMain in the jar gf-client-module.jar. It worked until java update 45.

回答1:

As of Update 45, JavaWebstart will no longer pass insecure properties to your application. All properties that are not prefixed with jnlp or javaws are considered insecure.

You either need to change loader.config to jnlp.loader.config (both in the JNLP as well as your java code), or you need to sign the JNLP (place an exact copy of your JNLP in JNLP-INF/APPLICATION.JNLP inside your jar and sign the jar).

According to this OpenJDK Bugreport this is an intentional change to resolve a security vulnerability

回答2:

There is no property with key "loader.config" in your system properties.that's why it returns null value to loaderConfig. When you pass null value to the StringReader constructor, it will throw NPE since the length method is invoked on the input Constructor argument (null value). Please see below

public StringReader(String s) {
        this.str = s;
        this.length = s.length();
    }

Hope this helps

回答3:

We searched a lot about this issue and luckily we found a solution that worked perfectly for us.

in our jnlp file we had:

<resources>
        <j2se version="1.5+"/>
        ...
</resources>

we have changed it in this mode:

<resources>
        <j2se version="1.6+" java-vm-args="-Djava.net.preferIPv4Stack=true"/>
        ...
</resources>

we found this solution here:

https://community.oracle.com/thread/2520987

Hope this may help you.

回答4:

This issue is solved in glassfish 4.1, until then downgrade your java to u21 or older.