Java 21
Run Java 21 Online
Compile and execute Java code instantly in a secure, isolated sandbox. No JDK setup, no installs — just write and run.
Compile and execute Java code instantly in a secure, isolated sandbox. No JDK setup, no installs — just write and run.
Java is the enterprise standard for building robust, cross-platform applications. With the JVM ecosystem, strong typing, and decades of battle-tested libraries, Java powers everything from Android apps to large-scale distributed systems.
Our sandbox runs Java 21 (LTS) with full JDK support.
Open a session once, then call execute repeatedly — variables, files, and installed packages persist between runs. Perfect for code interpreters and REPL-style agents.
# 1. Create a session curl -X POST https://api.sandboxapi.dev/v1/sessions \ -H "X-RapidAPI-Key: $KEY" \ -d '{"language":"java","idle_ttl":300}' # → {"id":"sess_abc","language":"java",...} # 2. Execute — first call curl -X POST https://api.sandboxapi.dev/v1/sessions/sess_abc/execute \ -H "X-RapidAPI-Key: $KEY" \ -d '{"code":"int x = 42; System.out.println(x);"}' # 3. Execute again — state carries over curl -X POST https://api.sandboxapi.dev/v1/sessions/sess_abc/execute \ -H "X-RapidAPI-Key: $KEY" \ -d '{"code":"// Note: Java is compiled — sessions persist files, not REPL state"}'
Note: Java is a compiled language. Sessions persist installed packages and files on disk, but variable state does not carry between calls. Use multi-file submissions or write intermediate state to disk.
Integrate secure code execution into your own apps with our REST API. Free tier includes 500 executions per month.
Get API Key on RapidAPI
