LOCAL_PREBUILT_JNI_LIBS:

LOCAL_PREBUILT_JNI_LIBS is a variable used in Android.mk files to specify pre-built JNI libraries that are needed by the project. JNI (Java Native Interface) is a programming framework that enables Java code to call and be called by native applications or libraries written in C or C++.

When building an Android app that uses native code, the NDK (Native Development Kit) is used to compile the C/C++ code into a native library that can be accessed by the Java code through JNI. However, sometimes it's necessary to include pre-built native libraries that were compiled outside of the Android build system.

In such cases, the LOCAL_PREBUILT_JNI_LIBS variable is used to specify the path to the pre-built libraries and their associated header files, if any. The variable is typically defined in the Android.mk file of the module that requires the pre-built libraries.

For example, to include a pre-built library named libfoo.so located in the /path/to/libfoo directory, the following lines would be added to the Android.mk file:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := foo
LOCAL_SRC_FILES := libfoo.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include

include $(PREBUILT_SHARED_LIBRARY)

Here, the LOCAL_MODULE variable specifies the name of the module that will be built, LOCAL_SRC_FILES specifies the name of the pre-built library file, and LOCAL_EXPORT_C_INCLUDES specifies the path to any header files needed by the library.

The include $(PREBUILT_SHARED_LIBRARY) line tells the build system to include the pre-built library in the module being built.