ClassUtils: be defensive when caching annotations

This avoids the following exception when injecting the
application context into the ImageJ gateway:

java.lang.UnsupportedClassVersionError: net/imagej/ops/OpService : Unsupported major.minor version 52.0
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2625)
	at java.lang.Class.getDeclaredMethods(Class.java:1868)
	at org.scijava.util.ClassUtils.cacheAnnotatedObjects(ClassUtils.java:507)
	at org.scijava.Context.inject(Context.java:377)
	at org.scijava.AbstractContextual.setContext(AbstractContextual.java:68)
	at org.scijava.AbstractGateway.<init>(AbstractGateway.java:85)
	at net.imagej.ImageJ.<init>(ImageJ.java:90)

Author: ctrueden

src/main/java/org/scijava/util/ClassUtils.java

@@ -358,7 +358,7 @@ public static <A extends Annotation> List<Method> getAnnotatedMethods(
 			cachedMethods = methodCache.getList(c, annotationClass);
 		}
 
-		methods.addAll(cachedMethods);
+		if (cachedMethods != null) methods.addAll(cachedMethods);
 	}
 
 	/**
@@ -501,15 +501,20 @@ else if (methodCache.getList(scannedClass, annotationClass) != null) {
 				final Class<? extends AnnotatedElement> objectClass =
 					query.get(annotationClass);
 
-				// Methods
-				if (Method.class.isAssignableFrom(objectClass)) {
-					populateCache(scannedClass, inherited, annotationClass, methodCache,
-						scannedClass.getDeclaredMethods());
+				try {
+					// Methods
+					if (Method.class.isAssignableFrom(objectClass)) {
+						populateCache(scannedClass, inherited, annotationClass, methodCache,
+							scannedClass.getDeclaredMethods());
+					}
+					// Fields
+					else if (Field.class.isAssignableFrom(objectClass)) {
+						populateCache(scannedClass, inherited, annotationClass, fieldCache,
+							scannedClass.getDeclaredFields());
+					}
 				}
-				// Fields
-				else if (Field.class.isAssignableFrom(objectClass)) {
-					populateCache(scannedClass, inherited, annotationClass, fieldCache,
-						scannedClass.getDeclaredFields());
+				catch (final Throwable t) {
+					// NB: No action needed?
 				}
 			}
 		}