Added null check when getting manifest attributes for case of jar without manifest

* netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java: (getManifestAttribute) added check fo null manifest to prevent npe.
* /tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java: added test for  npe from getManifestAttribute
* tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java: (createJarWithContents) enhanced to be able to create jar without manifest.

4 files changed, 64 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 57e632c..64198a9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2013-11-26  Jiri Vanek  <[email protected]>
+
+	* netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java: (getManifestAttribute)
+	added check for null manifest to prevent npe.
+	* /tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java:
+	added test for npe from getManifestAttribute
+	* tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java:
+	(createJarWithContents) enhanced to be able to create jar without manifest.
+
 2013-11-25  Jiri Vanek  <[email protected]>
 
 	* netx/net/sourceforge/jnlp/JNLPFile.java: (TITLE_NOT_FOUND) new constant
diff --git a/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java b/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java
index 3be3623..324bbc6 100644
--- a/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java
+++ b/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java
@@ -900,8 +900,12 @@ public class JNLPClassLoader extends URLClassLoader {
             JarFile mainJar = null;
             try {
                 mainJar = new JarFile(f);
-                attributeValue = mainJar.getManifest().
-                        getMainAttributes().getValue(attribute);
+                Manifest manifest = mainJar.getManifest();
+                if (manifest == null || manifest.getMainAttributes() == null){
+                    //yes, jars without manifest exists
+                    return null;
+                }
+                attributeValue = manifest.getMainAttributes().getValue(attribute);
             } catch (IOException ioe) {
                 attributeValue = null;
             } finally {
diff --git a/tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java b/tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java
index e713512..26de7b6 100644
--- a/tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java
+++ b/tests/netx/unit/net/sourceforge/jnlp/runtime/JNLPClassLoaderTest.java
@@ -51,6 +51,7 @@ import net.sourceforge.jnlp.cache.UpdatePolicy;
 import net.sourceforge.jnlp.mock.DummyJNLPFileWithJar;
 import net.sourceforge.jnlp.util.FileTestUtils;
 import net.sourceforge.jnlp.util.logging.NoStdOutErrTest;
+import org.junit.Assert;
 
 import org.junit.Test;
 
@@ -259,4 +260,38 @@ public class JNLPClassLoaderTest extends NoStdOutErrTest{
             }
         });
     }
+    
+    
+    @Test
+    public void tryNullManifest() throws Exception {
+        File tempDirectory = FileTestUtils.createTempDirectory();
+        File jarLocation = new File(tempDirectory, "test-npe.jar");
+        File dummyContent = File.createTempFile("dummy", "context", tempDirectory);
+        jarLocation.deleteOnExit();
+
+        /* Test with-out any attribute specified specified */
+        FileTestUtils.createJarWithoutManifestContents(jarLocation, dummyContent);
+
+        final Exception[] exs = new Exception[2];
+        final DummyJNLPFileWithJar jnlpFile = new DummyJNLPFileWithJar(jarLocation);
+        try {
+            final JNLPClassLoader classLoader = new JNLPClassLoader(jnlpFile, UpdatePolicy.ALWAYS);
+            assertNoFileLeak(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        assertEquals(null, classLoader.getManifestAttribute(jnlpFile.getJarLocation(), Attributes.Name.MAIN_CLASS));
+                        assertEquals(null, classLoader.getManifestAttribute(jnlpFile.getJarLocation(), Attributes.Name.IMPLEMENTATION_TITLE));
+                    } catch (Exception e) {
+                        exs[0] = e;
+                    }
+                }
+            });
+        } catch (Exception e) {
+            exs[1] = e;
+        }
+        Assert.assertNotNull(exs);
+        Assert.assertNull(exs[0]);
+        Assert.assertNull(exs[1]);
+    }
 }
diff --git a/tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java b/tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java
index 828d6a5..1ce4935 100644
--- a/tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java
+++ b/tests/test-extensions/net/sourceforge/jnlp/util/FileTestUtils.java
@@ -89,13 +89,25 @@ public class FileTestUtils {
     }
 
     /* Creates a jar in a temporary directory, with the given name & file contents */
+    static public void createJarWithoutManifestContents(File jarFile, File... fileContents) throws Exception{
+        createJarWithContents(jarFile, null, fileContents);
+    }
+    
+    /* Creates a jar in a temporary directory, with the given name & file contents */
     static public void createJarWithContents(File jarFile, Manifest manifestContents, File... fileContents)
             throws Exception {
         /* Manifest quite evilly ignores all attributes if we don't specify a version! 
          * Make sure it's set here. */
-        manifestContents.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+        if (manifestContents != null){
+            manifestContents.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+        }
 
-        JarOutputStream jarWriter = new JarOutputStream(new FileOutputStream(jarFile), manifestContents);
+        JarOutputStream jarWriter;
+        if (manifestContents == null){
+            jarWriter = new JarOutputStream(new FileOutputStream(jarFile));
+        } else {
+            jarWriter = new JarOutputStream(new FileOutputStream(jarFile), manifestContents);
+        }
         for (File file : fileContents) {
             jarWriter.putNextEntry(new JarEntry(file.getName()));
             FileInputStream fileReader = new FileInputStream(file);