Unable to run Java in sandbox in macOS

[mzs (Michael Smith)]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Java doesn’t seem to work inside the sandbox. Something about how /usr/bin/java enumerates the available JDKs is being blocked.

In the sandbox, both java -version and /usr/libexec/java_home -V give:

The operation couldn't be completed. Unable to locate a Java Runtime.
Please visit http://www.java.com for information on installing Java.

Outside the sandbox, /usr/lib/java_home -V lists the JVMs:

Matching Java Virtual Machines (3):
    25.0.1 (arm64) "Eclipse Adoptium" - "OpenJDK 25.0.1" /Library/Java/JavaVirtualMachines/temurin-25.jdk/Contents/Home
    21.0.5 (arm64) "Eclipse Adoptium" - "OpenJDK 21.0.5" /Users/me/Library/Java/JavaVirtualMachines/temurin-21.0.5/Contents/Home
    17.0.5 (arm64) "Eclipse Adoptium" - "OpenJDK 17.0.5" /Users/me/Library/Java/JavaVirtualMachines/temurin-17.0.5/Contents/Home
/Library/Java/JavaVirtualMachines/temurin-25.jdk/Contents/Home

If I actually symlink the bin/java binary from one of those into my workspace and tell the agent to run it in the sandbox, it works.

./runjava25

openjdk version "25.0.1" 2025-10-21 LTS
OpenJDK Runtime Environment Temurin-25.0.1+8 (build 25.0.1+8-LTS)
OpenJDK 64-Bit Server VM Temurin-25.0.1+8 (build 25.0.1+8-LTS, mixed mode, sharing)

Steps to Reproduce

Ask the agent to run java -version inside the sandbox

Operating System

MacOS

Version Information

Version: 2.5.17 (Universal)
VSCode Version: 1.105.1
Commit: 7b98dcb824ea96c9c62362a5e80dbf0d1aae4770
Date: 2026-02-17T05:58:33.110Z
Build Type: Stable
Release Track: Default
Electron: 39.3.0
Chromium: 142.0.7444.265
Node.js: 22.21.1
V8: 14.2.231.22-electron.0
OS: Darwin arm64 24.6.0

For AI issues: which model did you use?

Auto

Does this stop you from using Cursor

No - Cursor works, but with this issue

[mzs (Michael Smith)]

Oddly if I run the IDE from my terminal and set an explicit JAVA_HOME variable, java -version works inside the sandbox.

JAVA_HOME=/Users/me/Library/Java/JavaVirtualMachines/temurin-21.0.5/Contents/Home cursor .

[deanrie]

Hey, thanks for the detailed report.

This looks like a macOS sandbox limitation. /usr/libexec/java_home uses specific system paths for JDK discovery, and the sandbox blocks access to them. Glad you found a workaround with JAVA_HOME.

A few options:

1. Set a permanent JAVA_HOME. Add this to ~/.zshrc or ~/.bash_profile:

export JAVA_HOME=/Users/me/Library/Java/JavaVirtualMachines/temurin-21.0.5/Contents/Home

Then restart your terminal and open Cursor via cursor . so the sandbox inherits the variable.

2. Symlink inside the workspace (like you already did). If you need different versions per project, you can add a symlink in the project root and point the agent to ./runjava25 instead of java.

3. Legacy Terminal Tool. Try switching to the legacy terminal (Cursor Settings > Agents > Legacy Terminal Tool). The sandbox works differently there and might not block java_home.

Let me know if the workaround doesn’t fit your setup or if you want help configuring it.