How can I enable Java in MATLAB R2025a and newer?

I have installed R2025a and newer but see that java is not enabled. How can I enable it? 

Answer 1

[MathWorks Support Team]

Since MATLAB's own graphical user interface is no longer Java-based starting in R2025a, but instead utilizes JavaScript and HTML, Java is no longer automatically loaded at startup.

To check if MATLAB can use the version of Java you have installed, you can run an example command like the following:

>> java.lang.String("Hello World!")

This should output an empty string as a result and enable Java for the current MATLAB instance.

You can then verify that java was enabled by running the following command:

>> version -java

[Walter Roberson]

@Giovanni de amici comments,

when I input

java.lang.String(" ") 

Matlab responds

Unable to resolve the name 'java.lang.String'.

is this a sign that something else (beside java) is wrong with my R2025a ?

[Walter Roberson]

@Giovanni de amici

When I try on R2025a Update 1, on my MacOS Intel system,

java.lang.String(" ") 

ans =

 

works, as it does here on MATLAB Answers.

Note that I do not have -nojvm in effect.