java: mraa jni library now dynamically links to libmraa

libmraajava.so was statically linking to mraa object files causing
duplicate mraa platform instances if a UPM Java module was also loaded.

JNI functionality has been moved into src/java/mraajni.c. JVM object is
now set when JVM is loaded; see updates to src/java/mraajava.i.
This was necessary as the JVM object cannot be directly referenced from
mraa as it will not be available when building C/C++ examples.

Signed-off-by: Henry Bruce <henry.bruce@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

include/java/mraajni.h

@@ -0,0 +1,44 @@
+/*
+ * Author: Henry bruce <henry.bruce@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "jni.h"
+#include "mraa/types.h"
+
+void mraa_java_set_jvm(JavaVM* vm);
+void mraa_java_isr_callback(void *args);
+mraa_result_t mraa_java_attach_thread();
+void mraa_java_detach_thread();
+void* mraa_java_create_global_ref(void* args);
+void mraa_java_delete_global_ref(void* ref);
+
+#ifdef __cplusplus
+}
+#endif
+