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Using Java in standard library for Matlab

Java-based functions should work with any Java version compatible with the Matlab release. Matlab in general does not bundle Java from the factory installation, but Java may have been installed by a system administrator. One cannot assume that Java will or will not be present on a given Matlab installation.

Matlab's Java language interface was introduced in Matlab 6.0 R12 in the year 2000. Our optional Java backend functions use only factory Java class--no third-party Java libraries are used.

Java backend diagnostic functions

Tell Java Virtual Machine (JVM) version:

version("-java")

Get the Java API level:

stdlib.java.api()

Get the Java vendor:

stdlib.java.vendor()

Get the Java version:

stdlib.java.version()

Tell JVM details:

je = jenv

% Tell the JAVA_HOME directory
disp(je.Home)

As general information (not used by Matlab-stdlib), non-factory Java classes can be used in Matlab.

Configure Matlab JVM

The Matlab Java interface is like other Matlab external languages such as Python. Matlab JVM can be configured to a compatible Java library by using the jenv Matlab function.

macOS JVM configuration

For example, to use the JDK 17 on macOS download and extract the ARM64 Compressed Archive. Tell Matlab to use this JDK from the Matlab console by:

jenv("/path/to/jdk-17/Contents/Home")

Or for the Amazon Corretto JDK 11 on macOS:

jenv("/Library/Java/JavaVirtualMachines/amazon-corretto-11.jdk/Contents/Home/")

Windows JVM configuration

On Windows, obtain OpenJDK with WinGet, which installs under "$Env:ProgramFiles/Microsoft/jdk-*":

winget search Microsoft.OpenJDK

Suppose OpenJDK 25 is desired (Matlab R2026b and newer) and available like:

winget install Microsoft.OpenJDK.25

Then tell Matlab to use this JDK from the Matlab console by:

r = 'jdk-25*';
jp = ls(fullfile(getenv('ProgramFiles'), 'Microsoft', r));
mustBeTextScalar(jp)
jp = fullfile(getenv('ProgramFiles'), 'Microsoft', jp);
jenv(jp)

NOTE: if using ARM64 CPU with x86_64 Matlab under Microsoft Windows Prism emulation (this is true at least through R2026b), then use the x86_64 version of Microsoft OpenJDK instead of the ARM64 JDK, otherwise Matlab will not be able to load the JDK. Be sure to use "ZIP" download, not the "MSI" or "EXE" installers to avoid interfering with other programs, and extract the ZIP to a folder like "$Env:SystemDrive/openjdk-x86_64" and then use that path in the jenv() call.

Warning: Unable to load Java Runtime Environment: C:/Program Files/Microsoft/jdk-*-hotspot/bin/server/jvm.dll is not a valid Win32 application. Disabling Java support.

Factory Reset JRE

To revert back to the default JRE if Matlab can't start or has problems, from system Terminal (not within Matlab):

matlab_jenv factory