FindJNI

Find Java Native Interface (JNI) headers and libraries.

JNI enables Java code running in a Java Virtual Machine (JVM) or Dalvik Virtual Machine (DVM) on Android to call and be called by native applications and libraries written in other languages such as C and C++.

This module finds if Java is installed and determines where the include files and libraries are. It also determines what the name of the library is. The caller may set variable JAVA_HOME to specify a Java installation prefix explicitly.

Added in version 3.24: Added imported targets, components AWT, JVM, and Android NDK support. If no components are specified, the module defaults to an empty components list while targeting Android, and all available components otherwise.

When using Android NDK, the corresponding package version is reported and a specific release can be requested. At Android API level 31 and above, the additional NativeHelper component can be requested. NativeHelper is also exposed as an implicit dependency of the JVM component (only if this does not cause a conflict) which provides a uniform access to JVM functions.

Imported Targets

Added in version 3.24.

JNI::JNI

Main JNI target, defined only if jni.h was found.

JNI::AWT

Java AWT Native Interface (JAWT) library, defined only if component AWT was found.

JNI::JVM

Java Virtual Machine (JVM) library, defined only if component JVM was found.

JNI::NativeHelper

When targeting Android API level 31 and above, the import target will provide access to libnativehelper.so that exposes JVM functions such as JNI_CreateJavaVM.

Result Variables

This module sets the following result variables:

JNI_INCLUDE_DIRS

The include directories to use.

JNI_LIBRARIES

The libraries to use (JAWT and JVM).

JNI_FOUND

TRUE if JNI headers and libraries were found.

JNI_<component>_FOUND

Added in version 3.24.

TRUE if <component> was found.

JNI_VERSION

Full Android NDK package version (including suffixes such as -beta3 and -rc1) or undefined otherwise.

JNI_VERSION_MAJOR

Added in version 3.24.

Android NDK major version or undefined otherwise.

JNI_VERSION_MINOR

Added in version 3.24.

Android NDK minor version or undefined otherwise.

JNI_VERSION_PATCH

Added in version 3.24.

Android NDK patch version or undefined otherwise.

Cache Variables

The following cache variables are also available to set or use:

JAVA_AWT_LIBRARY

The path to the Java AWT Native Interface (JAWT) library.

JAVA_JVM_LIBRARY

The path to the Java Virtual Machine (JVM) library.

JAVA_INCLUDE_PATH

The include path to jni.h.

JAVA_INCLUDE_PATH2

The include path to machine-dependant headers jni_md.h and jniport.h. The variable is defined only if jni.h depends on one of these headers. In contrast, Android NDK jni.h can be typically used standalone.

JAVA_AWT_INCLUDE_PATH

The include path to jawt.h.