FindJava

Finds the Java installation and determines its runtime tools and development components.

Added in version 3.10: Support for Java 9+ version parsing.

Components

This module supports the following components:

Runtime: Finds the Java Runtime Environment used to execute Java byte-compiled applications.
Development: Finds development tools (java, javac, javah, jar, and javadoc). Specifying this component also implies the Runtime component.
IdlJ: Added in version 3.4.

Finds the Interface Description Language (IDL) to Java compiler.
JarSigner: Added in version 3.4.

Finds the signer and verifier tool for Java Archive (JAR) files.

Components can optionally be specified using the standard syntax with:

find_package(Java [COMPONENTS <components>...])

If no COMPONENTS are specified, the module searches for the Runtime component by default.

This module defines the following variables:

Java_FOUND: Boolean indicating whether Java with all specified components is found.
Java_<component>_FOUND: Boolean indicating whether the <component> is found.
Java_VERSION: Version of Java found. This is set to: <major>[.<minor>[.<patch>[.<tweak>]]].
Java_VERSION_MAJOR: The major version of Java found.
Java_VERSION_MINOR: The minor version of Java found.
Java_VERSION_PATCH: The patch version of Java found.
Java_VERSION_TWEAK: The tweak version of Java found (part after the underscore character _).
Java_VERSION_STRING: Version of Java found, e.g., 1.6.0_12.

Note

Java_VERSION and Java_VERSION_STRING are not guaranteed to be identical. For example, some Java versions may return: Java_VERSION_STRING = 1.8.0_17 and Java_VERSION = 1.8.0.17.

Another example is the Java OEM, with Java_VERSION_STRING = 1.8.0-oem and Java_VERSION = 1.8.0.

The following cache variables may also be set:

Java_JAVA_EXECUTABLE: The full path to the Java runtime.
Java_JAVAC_EXECUTABLE: The full path to the Java compiler.
Java_JAVAH_EXECUTABLE: The full path to the Java header generator.
Java_JAVADOC_EXECUTABLE: The full path to the Java documentation generator.
Java_IDLJ_EXECUTABLE: Added in version 3.4.

The full path to the Java idl compiler.
Java_JAR_EXECUTABLE: The full path to the Java archiver.
Java_JARSIGNER_EXECUTABLE: Added in version 3.4.

The full path to the Java jar signer.

This module accepts the following variables:

JAVA_HOME: The caller can set this variable to specify the installation directory of Java explicitly.

Finding Java:

find_package(Java)

Finding Java with at least the specified minimum version:

find_package(Java 1.8)

Finding Java and making it required (if Java is not found, processing stops with an error message):

find_package(Java 1.8 REQUIRED)

Specifying the needed Java components to find:

find_package(Java COMPONENTS Development JarSigner)