Catch ASM ClassReader's IllegalArgumentException and turn it into a m…

…ore expressive exception, hinting at the class file version

Issue: SPR-10292

spring-core/src/main/java/org/springframework/core/type/classreading/SimpleMetadataReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@
 import java.io.InputStream;
 
 import org.springframework.asm.ClassReader;
+import org.springframework.core.NestedIOException;
 import org.springframework.core.io.Resource;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.ClassMetadata;
@@ -47,10 +48,14 @@ final class SimpleMetadataReader implements MetadataReader {
 
 	SimpleMetadataReader(Resource resource, ClassLoader classLoader) throws IOException {
 		InputStream is = new BufferedInputStream(resource.getInputStream());
-		ClassReader classReader = null;
+		ClassReader classReader;
 		try {
 			classReader = new ClassReader(is);
 		}
+		catch (IllegalArgumentException ex) {
+			throw new NestedIOException("ASM ClassReader failed to parse class file - " +
+					"probably due to a new Java class file version that isn't supported yet: " + resource, ex);
+		}
 		finally {
 			is.close();
 		}
@@ -64,6 +69,7 @@ final class SimpleMetadataReader implements MetadataReader {
 		this.resource = resource;
 	}
 
+
 	public Resource getResource() {
 		return this.resource;
 	}