* moved makefile from jni to root directory

* copied orig makefile to makefile.windows
* since jdk 8 javah is outdated, but javac -h should be used instead.
* migrated libs, targets to linux (.dll --> .so,...)

README.md

-# Exercise repository for Java Native Interface (JNI)
-
-At times, it is necessary to use native codes (C/C++) to overcome the memory management and performance constraints in Java. Java supports native codes via the Java Native Interface (JNI). This repository contains a "Hello World" example for using the JNI which is based on this [tutorial](https://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html).
-
-
-# Prerequisites
-1. **Java Development Kit 8**
-2. **C/C++ Compiler**
-    * GCC compiler and Makefile ([Read "GCC and Make"](https://www3.ntu.edu.sg/home/ehchua/programming/cpp/gcc_make.html)) **or**
-    * Cygwin or MinGW on Windows ([Read "How to Setup Cygwin and MinGW](https://www3.ntu.edu.sg/home/ehchua/programming/howto/Cygwin_HowTo.html)
-3. **Eclipse for Java Developers** with **C/C++ Development Tool (CDT) extension** installed ([Read "Eclipse CDT"](https://www3.ntu.edu.sg/home/ehchua/programming/howto/EclipseCpp_HowTo.html)).
-
-# Clone project
-```git clone https://es.technikum-wien.at/embedded_systems_public/Java-Exercises-7-JNI-HW-Interfacing.git```
-
-# Create Eclipse project
-
-1. *File/New/Project*
-2. Select *General/Project* and click *Next*
-3. Unselect *Use default location* and browse to cloned diretory, click *OK*
-4. Enter *Project name* and click *Finish*
-
-# Build project
-
-Building the project involves two steps
-
-1. Building Java code
-    * Click on *Project/Build All*. This is not necessary if *Build Automatically* is selected.
-2. Building native code either on command line or using the configured Eclipse build targets
-    * Command line:```cd jni && make``` or
-    * Double click on *jni/Build Targets/all*
-
-# Run project
-
-Before the application can be run, you must build the native code and provide the library path to the "hello.dll" file, if it is not located in the *current working directory*.
-This can be done via the VM argument ```-Djava.library.path```. Right-click on the project and select *Run As/Run Configurations*, then select *Java Application*. In the *Main tab*, enter the main class "HelloJNI" and in *Arguments/VM Arguments*, enter ```-Djava.library.path=jni```. Finally click on *Run*.
-
-You should see the output "Hello World!" displayed on the console.
-
-## Command line
-
-```java -Djava.library.path=jni -cp bin java_exercises7_1_1.HelloJNI```
-
-
-
-
+# Exercise repository for Java Native Interface (JNI)
+
+At times, it is necessary to use native codes (C/C++) to overcome the memory management and performance constraints in Java. Java supports native codes via the Java Native Interface (JNI). This repository contains a "Hello World" example for using the JNI which is based on this [tutorial](https://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html).
+
+
+# Prerequisites
+1. **Java Development Kit >= 8**
+2. **C/C++ Compiler**	
+	* **[windows-only]**: Cygwin or MinGW on Windows ([Read "How to Setup Cygwin and MinGW](https://www3.ntu.edu.sg/home/ehchua/programming/howto/Cygwin_HowTo.html)
+    * GCC compiler and Makefile ([Read "GCC and Make"](https://www3.ntu.edu.sg/home/ehchua/programming/cpp/gcc_make.html))
+3. **Eclipse for Java Developers** with **C/C++ Development Tool (CDT) extension** installed ([Read "Eclipse CDT"](https://www3.ntu.edu.sg/home/ehchua/programming/howto/EclipseCpp_HowTo.html)).
+
+# Clone project
+```git clone https://es.technikum-wien.at/embedded_systems_public/Java-Exercises-7-JNI-HW-Interfacing.git```
+
+# Create Eclipse project
+
+1. *File/New/Project*
+2. Select *General/Project* and click *Next*
+3. Unselect *Use default location* and browse to cloned diretory, click *OK*
+4. Enter *Project name* and click *Finish*
+
+# Build project
+
+Building the project involves two steps
+
+1. Building the Java code and the native code using the make targets:
+    * Command line:```make```
+
+# Run project
+
+Before the application can be run, you must provide the library path to the native library (Linux: ```libhello.so```, Windows: ```hello.dll```) file, if it is not located in the *current working directory*.
+This can be done via the VM argument ```-Djava.library.path```. Right-click on the project and select *Run As/Run Configurations*, then select *Java Application*. In the *Main tab*, enter the main class "HelloJNI" and in *Arguments/VM Arguments*, enter ```-Djava.library.path=jni```. Finally click on *Run*.
+
+You should see the output "Hello World!" displayed on the console.
+
+## Command line
+
+### Example 1
+```java -Djava.library.path=jni -cp bin java_exercises7_1_1.HelloJNI```
+### Example 2
+```java -Djava.library.path=jni -cp bin java_exercises7_2_1.HelloJNI```
+
+
+
+

jni/makefile → jni/makefile.windows

-# Define a variable for classpath
-CLASS_PATH = ../bin
-JAVA_HOME=C:\Program Files (x86)\Java\jdk1.8.0_131
-
-# Define a virtual path for .class in the bin directory
-vpath %.class $(CLASS_PATH)
-
-all : hello.dll java_exercises7_2_1_HelloJNI.dll
-
-# Targets for java_exercises_7_1_1
-# $@ matches the target, $< matches the first dependancy
-hello.dll : HelloJNI.o
-	gcc -Wl,--add-stdcall-alias -shared -o $@ $<
-
-# $@ matches the target, $< matches the first dependancy
-HelloJNI.o : HelloJNI.c HelloJNI.h
-	gcc -I"$(JAVA_HOME)\include" -I"$(JAVA_HOME)\include\win32" -c $< -o $@
-
-# $* matches the target filename without the extension
-HelloJNI.h : java_exercises7_1_1/HelloJNI.class
-	javah -o HelloJNI.h -classpath $(CLASS_PATH) java_exercises7_1_1.$*
-	
-# Targets for java_exercises_7_2_1	
-# $@ matches the target, $< matches the first dependancy
-java_exercises7_2_1_HelloJNI.dll : java_exercises7_2_1_HelloJNI.o
-	gcc -Wl,--add-stdcall-alias -shared -o $@ $<
-
-# $@ matches the target, $< matches the first dependancy
-java_exercises7_2_1_HelloJNI.o : java_exercises7_2_1_HelloJNI.c java_exercises7_2_1_HelloJNI.h
-	gcc -I"$(JAVA_HOME)\include" -I"$(JAVA_HOME)\include\win32" -c $< -o $@
-	
-java_exercises7_2_1_HelloJNI.h : java_exercises7_2_1/HelloJNI.class
-	javah -classpath $(CLASS_PATH) java_exercises7_2_1.HelloJNI
-
-clean :
+# Define a variable for classpath
+CLASS_PATH = ../bin
+JAVA_HOME=C:\Program Files (x86)\Java\jdk1.8.0_131
+
+# Define a virtual path for .class in the bin directory
+vpath %.class $(CLASS_PATH)
+
+all : hello.dll java_exercises7_2_1_HelloJNI.dll
+
+# Targets for java_exercises_7_1_1
+# $@ matches the target, $< matches the first dependancy
+hello.dll : HelloJNI.o
+	gcc -Wl,--add-stdcall-alias -shared -o $@ $<
+
+# $@ matches the target, $< matches the first dependancy
+HelloJNI.o : HelloJNI.c HelloJNI.h
+	gcc -I"$(JAVA_HOME)\include" -I"$(JAVA_HOME)\include\win32" -c $< -o $@
+
+# $* matches the target filename without the extension
+HelloJNI.h : java_exercises7_1_1/HelloJNI.class
+	javah -o HelloJNI.h -classpath $(CLASS_PATH) java_exercises7_1_1.$*
+	
+# Targets for java_exercises_7_2_1	
+# $@ matches the target, $< matches the first dependancy
+java_exercises7_2_1_HelloJNI.dll : java_exercises7_2_1_HelloJNI.o
+	gcc -Wl,--add-stdcall-alias -shared -o $@ $<
+
+# $@ matches the target, $< matches the first dependancy
+java_exercises7_2_1_HelloJNI.o : java_exercises7_2_1_HelloJNI.c java_exercises7_2_1_HelloJNI.h
+	gcc -I"$(JAVA_HOME)\include" -I"$(JAVA_HOME)\include\win32" -c $< -o $@
+	
+java_exercises7_2_1_HelloJNI.h : java_exercises7_2_1/HelloJNI.class
+	javah -classpath $(CLASS_PATH) java_exercises7_2_1.HelloJNI
+
+clean :
 	rm HelloJNI.h HelloJNI.o hello.dll java_exercises7_2_1_HelloJNI.dll java_exercises7_2_1_HelloJNI.h java_exercises7_2_1_HelloJNI.o
\ No newline at end of file

makefile

+# Define a variable for classpath
+CLASS_PATH = ./bin
+JAVA_HOME=/usr/lib/jvm/default-java/
+JNI_DIR=./jni
+SRC_DIR=./src
+
+# Define a virtual path for .class in the bin directory
+vpath %.class $(CLASS_PATH)
+
+all : $(JNI_DIR)/libhello.so $(JNI_DIR)/libjava_exercises7_2_1_HelloJNI.so
+
+# Targets for java_exercises_7_1_1
+# $@ matches the target, $< matches the first dependancy
+$(JNI_DIR)/libhello.so : $(JNI_DIR)/HelloJNI.o
+	gcc -W -shared -o $@ $<
+
+# $@ matches the target, $< matches the first dependancy
+$(JNI_DIR)/HelloJNI.o : $(JNI_DIR)/HelloJNI.c $(JNI_DIR)/HelloJNI.h
+	gcc -I"$(JAVA_HOME)/include" -I"$(JAVA_HOME)/include/linux" -I"$(JNI_DIR)" -c $< -o $@
+
+# $* matches the target filename without the extension
+$(JNI_DIR)/HelloJNI.h :
+	javac -h $(JNI_DIR) -d $(CLASS_PATH) $(SRC_DIR)/java_exercises7_1_1/HelloJNI.java
+	
+# Targets for java_exercises_7_2_1	
+# $@ matches the target, $< matches the first dependancy
+$(JNI_DIR)/libjava_exercises7_2_1_HelloJNI.so : $(JNI_DIR)/java_exercises7_2_1_HelloJNI.o
+	gcc -W -shared -o $@ $<
+
+# $@ matches the target, $< matches the first dependancy
+$(JNI_DIR)/java_exercises7_2_1_HelloJNI.o : $(JNI_DIR)/java_exercises7_2_1_HelloJNI.c $(JNI_DIR)/java_exercises7_2_1_HelloJNI.h
+	gcc -I"$(JAVA_HOME)/include" -I"$(JAVA_HOME)/include/linux" -I"$(JNI_DIR)" -c $< -o $@
+	
+$(JNI_DIR)/java_exercises7_2_1_HelloJNI.h :
+	javac -h $(JNI_DIR) -d $(CLASS_PATH) $(SRC_DIR)/java_exercises7_2_1/HelloJNI.java
+
+clean :
+	rm -Rf $(JNI_DIR)/*.h $(JNI_DIR)/*.o $(JNI_DIR)/*.so $(JNI_DIR)/*.dll $(CLASS_PATH)/*
\ No newline at end of file