javac: command not found

javac: command not found means the Java compiler is not installed or not on PATH. You need a JDK (not just a JRE) to compile .java files into bytecode.

What It Means

The shell searched every directory in your $PATH environment variable and couldn’t find an executable named javac. Unlike java (the runtime), javac only ships with the JDK (Java Development Kit), not the JRE.

Why It Happens

• You only installed the JRE, not the JDK.
• The JDK is installed but its bin/ directory isn’t in your PATH.
• JAVA_HOME is not set or points to the wrong location.
• You’re on a minimal Docker image or headless server with no JDK.

How to Fix It

1. Check if a JDK is already installed

# Look for javac anywhere on the system
which javac
find / -name javac -type f 2>/dev/null

# On macOS with Homebrew
brew list | grep jdk

2. Install a JDK

Ubuntu / Debian:

sudo apt update
sudo apt install default-jdk

Fedora / RHEL:

sudo dnf install java-latest-openjdk-devel

macOS (Homebrew):

brew install openjdk

Windows: Download the JDK installer from oracle.com and run it. Check “Add to PATH” during setup.

3. Locate the JDK installation

After installing, find where javac lives:

# Common locations
/usr/bin/javac
/usr/lib/jvm/java-17-openjdk-amd64/bin/javac
/Library/Java/JavaVirtualMachines/openjdk.jdk/Contents/Home/bin/javac

4. Add JDK to PATH

Add this to your ~/.bashrc or ~/.zshrc:

export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
export PATH=$JAVA_HOME/bin:$PATH

Replace the path with your actual JDK location. Then reload:

source ~/.bashrc

5. Verify the fix

javac -version
# Output: javac 17.0.9