oracle/graal · error · AssertionError

The java.home system property is not set

Error message

The java.home system property is not set

What it means

Error "The java.home system property is not set" thrown in oracle/graal.

Source

Thrown at sdk/src/org.graalvm.home/src/org/graalvm/home/impl/DefaultHomeFinder.java:183

        final Path home;
        if (ImageInfo.inImageRuntimeCode()) {
            final String graalvmHomeValue = System.getProperty("org.graalvm.home");
            if (graalvmHomeValue != null) {
                verbose("GraalVM home already set to: ", graalvmHomeValue);
                home = Paths.get(graalvmHomeValue);
            } else {
                home = getGraalVmHomeNative();
                verbose("Found GraalVM home: ", home);
                if (home == null) {
                    return null;
                }
            }
            return home;
        } else {
            final String javaHomeProperty = System.getProperty("java.home");
            if (javaHomeProperty == null) {
                throw new AssertionError("The java.home system property is not set");
            }

            final Path javaHome = Paths.get(javaHomeProperty);
            if (!Files.exists(javaHome)) {
                throw new AssertionError("Java home is not reachable.");
            }

            if (Files.exists(javaHome.resolve(Paths.get("lib", "modules")))) {
                home = javaHome;
            } else {
                throw new AssertionError("Missing jimage in java.home: " + javaHome);
            }

            verbose("GraalVM home found by java.home property as: ", home);
            return home;
        }
    }

View on GitHub (pinned to a66e9ccd1d)

Solutions

1. Fix the condition reported by the error: The java.home system property is not set
2. Check the throwing call site and ensure its documented preconditions (argument values, types, environment, or configuration) are satisfied before the call.

Example fix

Validate inputs and environment so that the failing condition does not occur: The java.home system property is not set

When it happens

Trigger: Thrown at sdk/src/org.graalvm.home/src/org/graalvm/home/impl/DefaultHomeFinder.java:183 when the library encounters an invalid state.

Common situations: Occurs when a caller violates the contract guarded by this check: The java.home system property is not set

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/a0a1d9b573882e9f. Report an issue: GitHub.