[build] CMake: disable Java components by default

.github/workflows/cmake.yml

@@ -15,7 +15,7 @@ jobs:
           - os: ubuntu-22.04
             name: Linux
             container: wpilib/roborio-cross-ubuntu:2024-22.04
-            flags: "-DCMAKE_BUILD_TYPE=Release -DWITH_EXAMPLES=ON"
+            flags: "-DCMAKE_BUILD_TYPE=Release -DWITH_JAVA=ON -DWITH_EXAMPLES=ON"
           - os: macOS-14
             name: macOS
             container: ""

CMakeLists.txt

@@ -26,6 +26,7 @@ endif()
 
 set(WPILIB_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
+include(CMakeDependentOption)
 include(CPack)
 include(OptionValidation)
 
@@ -55,12 +56,18 @@ set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
 
 # Options for building certain parts of the repo. Everything is built by default.
 option(BUILD_SHARED_LIBS "Build with shared libs (needed for JNI)" ON)
-option(WITH_JAVA "Include Java and JNI in the build" ON)
+option(WITH_JAVA "Include Java and JNI in the build" OFF)
 option(WITH_JAVA_SOURCE "Build Java source jars" ${WITH_JAVA})
 option(WITH_CSCORE "Build cscore (needs OpenCV)" ON)
 option(WITH_NTCORE "Build ntcore" ON)
 option(WITH_WPIMATH "Build wpimath" ON)
-option(WITH_WPIUNITS "Build wpiunits" ON)
+cmake_dependent_option(
+    WITH_WPIUNITS
+    "Build wpiunits"
+    ON
+    WITH_JAVA
+    OFF
+)
 option(WITH_WPILIB "Build hal, wpilibc/j, and developerRobot (needs OpenCV)" ON)
 option(WITH_EXAMPLES "Build examples" OFF)
 option(WITH_TESTS "Build unit tests (requires internet connection)" ON)

README-CMAKE.md

@@ -52,7 +52,7 @@ The following build options are available:
   * This option will build C++ examples.
 * `WITH_GUI` (ON Default)
   * This option will build GUI items. If this is off, and `WITH_SIMULATION_MODULES` is on, the simulation GUI will not be built.
-* `WITH_JAVA` (ON Default)
+* `WITH_JAVA` (OFF Default)
   * This option will enable Java and JNI builds. If this is on, `BUILD_SHARED_LIBS` must be on. Otherwise CMake will error.
 * `WITH_JAVA_SOURCE` (`WITH_JAVA` Default)
   * This option will build Java source JARs for each enabled Java library. This does not require `WITH_JAVA` to be on, allowing source JARs to be built without the compiled JARs if desired.
@@ -66,7 +66,7 @@ The following build options are available:
   * This option will build the HAL and wpilibc/j during the build. The HAL is the simulation HAL, unless the external HAL options are used. The CMake build has no capability to build for the roboRIO.
 * `WITH_WPIMATH` (ON Default)
   * This option will build the wpimath library. This option must be on to build wpilib.
-* `WITH_WPIUNITS` (ON Default)
+* `WITH_WPIUNITS` (`WITH_JAVA` Default)
   * This option will build the wpiunits library. This option must be on to build the Java wpimath library and requires `WITH_JAVA` to also be on.
 * `OPENCV_JAVA_INSTALL_DIR`
   * Set this option to the location of the archive of the OpenCV Java bindings (it should be called opencv-xxx.jar, with the x'es being version numbers). NOTE: set it to the LOCATION of the file, not the file itself!