diff --git a/Makefile b/Makefile
index e815409e..ada7e905 100644
--- a/Makefile
+++ b/Makefile
@@ -1,18 +1,26 @@
 .PHONY: build_ext tests
 
+JAVAC_OPTS=-target 1.6 -source 1.6
+JAVAC=javac $(JAVAC_OPTS)
+
 build_ext:
-	javac jnius/src/org/jnius/NativeInvocationHandler.java
+	$(JAVAC) jnius/src/org/jnius/NativeInvocationHandler.java
 	python setup.py build_ext --inplace -f -g
 
+clean:
+	find . -name "*.class" -exec rm {} \;
+	rm -rf build
+
 html:
 	$(MAKE) -C docs html
 
 tests: build_ext
-	cd tests && javac org/jnius/HelloWorld.java
-	cd tests && javac org/jnius/BasicsTest.java
-	cd tests && javac org/jnius/MultipleMethods.java
-	cd tests && javac org/jnius/SimpleEnum.java
-	cd tests && javac org/jnius/InterfaceWithPublicEnum.java
-	cd tests && javac org/jnius/ClassArgument.java
-	cd tests && javac org/jnius/MultipleDimensions.java
+	cd tests && $(JAVAC) org/jnius/HelloWorld.java
+	cd tests && $(JAVAC) org/jnius/BasicsTest.java
+	cd tests && $(JAVAC) org/jnius/MultipleMethods.java
+	cd tests && $(JAVAC) org/jnius/SimpleEnum.java
+	cd tests && $(JAVAC) org/jnius/InterfaceWithPublicEnum.java
+	cd tests && $(JAVAC) org/jnius/ClassArgument.java
+	cd tests && $(JAVAC) org/jnius/MultipleDimensions.java
+	cp jnius/src/org/jnius/NativeInvocationHandler.class tests/org/jnius
 	cd tests && env PYTHONPATH=..:$(PYTHONPATH) nosetests-2.7 -v
diff --git a/tests/test_proxy.py b/tests/test_proxy.py
index 7a5d7be4..c7630ce4 100644
--- a/tests/test_proxy.py
+++ b/tests/test_proxy.py
@@ -1,4 +1,5 @@
 from jnius import autoclass, java_method, PythonJavaClass, cast
+from nose.tools import *
 
 print '1: declare a TestImplem that implement Collection'
 
@@ -104,7 +105,7 @@ def bad_signature(self, *args):
         pass
 
 
-print '2: instanciate the class, with some data'
+print '2: instantiate the class, with some data'
 a = TestImplem(*range(10))
 print a
 print dir(a)
@@ -150,4 +151,11 @@ def bad_signature(self, *args):
 #print Collections.shuffle(a2)
 
 # test bad signature
-TestBadSignature()
+threw = False
+try:
+    TestBadSignature()
+except Exception:
+    threw = True
+
+if not threw:
+    raise Exception("Failed to throw for bad signature")