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:
Example (pseudo-code for a Windows launcher): cannot load 32-bit swt libraries on 64-bit jvm
<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: Replace the swt