diff --git a/bindings/java/Makefile b/bindings/java/Makefile
index c92a253..99afc6b 100644
--- a/bindings/java/Makefile
+++ b/bindings/java/Makefile
@@ -8,23 +8,27 @@ ifeq ($(OS),Windows_NT)
 	LIBRARY_RESOURCE=ckzg4844jni.dll
 else
 	CLANG_EXECUTABLE=clang
-    	GRADLE_COMMAND=./gradlew
+	GRADLE_COMMAND=./gradlew
 	UNAME_S := $(shell uname -s)
 	ifeq ($(UNAME_S),Linux)
 	CLANG_FLAGS=-fPIC -shared
-    	JNI_INCLUDE_FOLDER=linux
-    	LIBRARY_RESOURCE=libckzg4844jni.so
+	JNI_INCLUDE_FOLDER=linux
+	LIBRARY_RESOURCE=libckzg4844jni.so
 	endif
 	ifeq ($(UNAME_S),Darwin)
 		ifeq ($(JAVA_HOME),)
 			JAVA_HOME := $(shell /usr/libexec/java_home)
 		endif
 	CLANG_FLAGS=-dynamiclib
-    	JNI_INCLUDE_FOLDER=darwin
-    	LIBRARY_RESOURCE=libckzg4844jni.dylib
+	JNI_INCLUDE_FOLDER=darwin
+	LIBRARY_RESOURCE=libckzg4844jni.dylib
 	endif
 endif
 
+ifeq ($(JAVA_HOME),)
+$(error JAVA_HOME is not set and autodetection failed)
+endif
+
 all: build test
 
 build: