ReturnAsJavaObject[expr]
causes a Java method call or field access during the evaluation of expr to return its result as an object reference (a JavaObject expression), not a value.


ReturnAsJavaObject
ReturnAsJavaObject[expr]
causes a Java method call or field access during the evaluation of expr to return its result as an object reference (a JavaObject expression), not a value.
Details and Options
- To use ReturnAsJavaObject, you first need to load J/Link using Needs["JLink`"].
- Most Java objects are returned as references normally, but those that have a meaningful Wolfram Language representation are returned "by value". Such objects include strings, arrays, and the so-called wrapper classes like java.lang.Integer. ReturnAsJavaObject overrides the normal behavior and forces any object returned to the Wolfram Language to be sent only as a reference.
- Typically used to avoid needlessly sending large arrays of numbers back and forth between Java and the Wolfram Language.
- You can use ReturnAsJavaObject to cause only a reference to be sent, then use the JavaObjectToExpression function at the end if the final value is needed.
Tech Notes
Related Guides
Text
Wolfram Research (2007), ReturnAsJavaObject, Wolfram Language function, https://reference.wolfram.com/language/JLink/ref/ReturnAsJavaObject.html.
CMS
Wolfram Language. 2007. "ReturnAsJavaObject." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/JLink/ref/ReturnAsJavaObject.html.
APA
Wolfram Language. (2007). ReturnAsJavaObject. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/JLink/ref/ReturnAsJavaObject.html
BibTeX
@misc{reference.wolfram_2025_returnasjavaobject, author="Wolfram Research", title="{ReturnAsJavaObject}", year="2007", howpublished="\url{https://reference.wolfram.com/language/JLink/ref/ReturnAsJavaObject.html}", note=[Accessed: 15-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_returnasjavaobject, organization={Wolfram Research}, title={ReturnAsJavaObject}, year={2007}, url={https://reference.wolfram.com/language/JLink/ref/ReturnAsJavaObject.html}, note=[Accessed: 15-August-2025]}