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.
Make sure you choose (e.g., Windows 64-bit , Linux 64-bit , macOS 64-bit ).
<dependency> <groupId>org.eclipse.platform</groupId> <artifactId>org.eclipse.swt.win32.win32.x86_64</artifactId> <version>3.125.0</version> </dependency> The classifier ( win32.win32.x86_64 ) encodes both OS and architecture. For other platforms:
| 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 | cannot load 32-bit swt libraries on 64-bit jvm
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.
dependencies implementation 'org.eclipse.platform:org.eclipse.swt.win32.win32.x86_64:3.125.0'
java -version Look for 64-Bit in the output. Example: java -d32 -jar yourapp
Example (pseudo-code for a Windows launcher):
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.
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. Instead, use a launcher script that adds the
dumpbin /headers swt-win32.dll | find "machine" Or on Linux/macOS:
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:
For Gradle:
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: