diff --git a/java/src/CMakeLists.txt b/java/src/CMakeLists.txt
index dc9d287..d1b7b0a 100644
--- a/java/src/CMakeLists.txt
+++ b/java/src/CMakeLists.txt
@@ -1,6 +1,6 @@
 find_package(Java)
 
-set(DEFAULT_JAVACFLAGS "-target 1.5")
+set(DEFAULT_JAVACFLAGS "-source 1.5 -target 1.5")
 set(JAVACFLAGS ${DEFAULT_JAVACFLAGS} CACHE STRING
   "Java compiler flags (Default: ${DEFAULT_JAVACFLAGS})")
 message(STATUS "Java compiler flags = ${JAVACFLAGS}")