Windows 3.10.0 crashes on startup: UnsatisfiedLinkError - swt-gdip-win32 missing (stripped from build)

[Al-Kom]

Description

Angry IP Scanner 3.10.0 fails to start on Windows (both the portable ipscan-3.10.0-win.exe and the official ipscan-3.10.0-setup.exe installer with bundled Java 25). The main window fails to render with an UnsatisfiedLinkError because SWT's swt-gdip-win32-*.dll cannot be found.

Steps to reproduce

1. Download ipscan-3.10.0-win.exe (or install via ipscan-3.10.0-setup.exe) on Windows 10/11 x86_64
2. Run it
3. Application throws SWTException / UnsatisfiedLinkError while drawing the main window and crashes

Error

org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons:
no swt-gdip-win32-4973r12 in java.library.path: ...
no swt-gdip-win32 in java.library.path: ...
no swt-gdip in java.library.path: ...
Can't load library: C:\Users.swt\lib\win32\x86_64\swt-gdip-win32-4973r12.dll
Can't load library: C:\Users.swt\lib\win32\x86_64\swt-gdip-win32.dll
Can't load library: C:\Users.swt\lib\win32\x86_64\swt-gdip.dll
)
at org.eclipse.swt.SWT.error(SWT.java:4934)
at org.eclipse.swt.SWT.error(SWT.java:4849)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4136)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3752)
at net.azib.ipscan.gui.GUI.showMainWindow(GUI.java:56)
at net.azib.ipscan.Main.main(Main.java:62)
Caused by: java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons:
...
at org.eclipse.swt.internal.gdip.Gdip.(Gdip.java:21)
at org.eclipse.swt.internal.gdip.GdiplusStartupInput.(GdiplusStartupInput.java:25)
at org.eclipse.swt.graphics.Device.checkGDIP(Device.java:226)
at org.eclipse.swt.graphics.Transform.(Transform.java:144)
at org.eclipse.swt.graphics.Transform.(Transform.java:75)
at org.eclipse.swt.graphics.GC.drawImage(GC.java:1045)
at org.eclipse.swt.widgets.Label.wmDrawChildImage(Label.java:571)
...

Root cause

In build.gradle, the packaging step strips several native SWT libraries from the shaded jar as apparently-unused, including swt-gdip-*.dll:

https://github.com/angryip/ipscan/blob/master/build.gradle

'swt-awt-.dll',
'swt-wgl-.dll',
'swt-gdip-.dll',
'swt-webkit-.dll',

However, SWT 3.134.0 (org.eclipse.platform:org.eclipse.swt.win32.win32.x86_64:3.134.0) actually needs swt-gdip-win32-*.dll at runtime — GC.drawImage() internally creates a Transform, which requires GDI+ (Device.checkGDIP → Gdip.<clinit>), and that in turn needs the native swt-gdip-win32 JNI bridge. This is hit unconditionally while drawing a Label image in the main window, so every Windows x86_64 user hits this crash on startup.

Confirmed workaround

Manually extracting swt-gdip-win32-4973r12.dll from the official org.eclipse.swt.win32.win32.x86_64-3.134.0.jar on Maven Central and placing it into %USERPROFILE%\.swt\lib\win32\x86_64\ fixes the crash — the app starts and runs normally. This confirms the DLL is simply missing from the distributed exe/jar, not a system-specific issue.

Suggested fix

Remove swt-gdip-*.dll from the strip/exclude list in build.gradle so it's bundled in the Windows build, since it's actually required by this SWT version.

Environment

• ipscan 3.10.0 (win.exe and setup.exe, both reproduce)
• Windows 10, x86_64
• Reproduces with both system Java 21 (Corretto) and the bundled Java 25 (installer)

[jgwallace3]

Workaround worked for me. Found the jar here: https://repo1.maven.org/maven2/org/eclipse/platform/org.eclipse.swt.win32.win32.x86_64/3.134.0/org.eclipse.swt.win32.win32.x86_64-3.134.0.jar, extracted the dlls and moved the indicated one to the .swt dir. Thx!

[nbcr]

Fix Available

The root cause has been identified and fixed: the swt-gdip-*.dll exclusion in �uild.gradle line 151 was preventing SWT 3.134.0's required GDI+ library from being bundled.

Solution

• PR Include swt-gdip-*.dll in Windows build #534: Fix merged into the official repository - removes the problematic exclusion
• v3.10.1 Release: A fixed version is available at https://github.com/nbcr/ipscan/releases/tag/v3.10.1 with:
  • ipscan-3.10.1-setup.exe (Windows installer with Java 25)
  • ipscan-3.10.1-win.exe (Windows portable)

Both include the GDI+ DLL bundled and the application starts without crashes.

Details

SWT 3.134.0 requires swt-gdip-win32-*.dll for graphics rendering. The GC.drawImage() method calls Device.checkGDIP(), which loads the native GDI+ library - this happens unconditionally when drawing the main window. Without the DLL, users get UnsatisfiedLinkError and the application crashes.

The fix simply removes the 'swt-gdip-*.dll' line from the exclude list in build.gradle, ensuring the library is bundled in Windows builds.

Tested and confirmed working on Windows 11 with Java 25.