file swt-gtk.so If it says x86 (32-bit) and your JVM is x64 (64-bit), you've found the mismatch. Method 1: Download the Correct SWT Build (Manual Fix) Go to the official SWT download page and select your platform + architecture.
For Gradle:
dumpbin /headers swt-win32.dll | find "machine" Or on Linux/macOS:
java -version Look for 64-Bit in the output. Example: cannot load 32-bit swt libraries on 64-bit jvm
java -d32 -jar yourapp.jar If you get Unrecognized option: -d32 , it's not available. Don't waste time here – fix the library instead. If you're distributing a desktop app, don't bundle a specific swt.jar . Instead, use a launcher script that adds the correct SWT JAR based on the detected platform and architecture.
If you've ever developed desktop applications using Eclipse SWT (Standard Widget Toolkit), you've likely been greeted by this frustrating error message at least once:
Make sure you choose (e.g., Windows 64-bit , Linux 64-bit , macOS 64-bit ). file swt-gtk
Example (pseudo-code for a Windows launcher):
Replace the swt.jar in your project's classpath with the correct one. If you use Maven, never just add swt.jar manually. Use the official Maven artifacts with classifiers:
Stick to Maven artifacts with platform classifiers, and you'll rarely see this error again. Have you run into other SWT native library issues? Share your war stories in the comments below. Example: java -d32 -jar yourapp
You can force your 64-bit JVM to run as 32-bit using -d32 , but this is rarely supported . Most 64-bit JDKs do not include 32-bit runtime support.
| Platform | Artifact ID (classifier part) | |---------------|----------------------------------------| | Windows 64-bit | org.eclipse.swt.win32.win32.x86_64 | | Linux 64-bit | org.eclipse.swt.gtk.linux.x86_64 | | macOS 64-bit | org.eclipse.swt.cocoa.macosx.x86_64 | | macOS ARM64 | org.eclipse.swt.cocoa.macosx.aarch64 |