Index: test/unit/org/openstreetmap/josm/gui/layer/MainLayerManagerTest.java
===================================================================
--- test/unit/org/openstreetmap/josm/gui/layer/MainLayerManagerTest.java	(revision 18392)
+++ test/unit/org/openstreetmap/josm/gui/layer/MainLayerManagerTest.java	(working copy)
@@ -2,9 +2,9 @@
 package org.openstreetmap.josm.gui.layer;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertSame;
-import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.Arrays;
 
@@ -16,6 +16,7 @@
 import org.openstreetmap.josm.gui.layer.MainLayerManager.ActiveLayerChangeEvent;
 import org.openstreetmap.josm.gui.layer.MainLayerManager.ActiveLayerChangeListener;
 import org.openstreetmap.josm.gui.util.GuiHelper;
+import org.openstreetmap.josm.tools.Logging;
 
 /**
  * Tests {@link MainLayerManager}.
@@ -145,7 +146,9 @@
     void testAddActiveLayerChangeListenerTwice() {
         CapturingActiveLayerChangeListener listener = new CapturingActiveLayerChangeListener();
         layerManagerWithActive.addActiveLayerChangeListener(listener);
-        assertThrows(IllegalArgumentException.class, () -> layerManagerWithActive.addActiveLayerChangeListener(listener));
+        Logging.clearLastErrorAndWarnings();
+        layerManagerWithActive.addActiveLayerChangeListener(listener);
+        assertFalse(Logging.getLastErrorAndWarnings().isEmpty());
     }
 
     /**
@@ -171,8 +174,9 @@
      */
     @Test
     void testRemoveActiveLayerChangeListenerNotInList() {
-        assertThrows(IllegalArgumentException.class,
-                () -> layerManagerWithActive.removeActiveLayerChangeListener(new CapturingActiveLayerChangeListener()));
+        Logging.clearLastErrorAndWarnings();
+        layerManagerWithActive.removeActiveLayerChangeListener(new CapturingActiveLayerChangeListener());
+        assertFalse(Logging.getLastErrorAndWarnings().isEmpty());
     }
 
     /**
Index: tools/eclipse/JOSM (Java 8).launch
===================================================================
--- tools/eclipse/JOSM (Java 8).launch	(revision 18392)
+++ tools/eclipse/JOSM (Java 8).launch	(working copy)
@@ -9,10 +9,10 @@
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_ATTR_USE_ARGFILE" value="false"/>
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_SHOW_CODEDETAILS_IN_EXCEPTION_MESSAGES" value="true"/>
     <booleanAttribute key="org.eclipse.jdt.launching.ATTR_USE_CLASSPATH_ONLY_JAR" value="false"/>
-    <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+    <stringAttribute key="org.eclipse.jdt.launching.JRE_CONTAINER" value="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8/"/>
     <stringAttribute key="org.eclipse.jdt.launching.MAIN_TYPE" value="org.openstreetmap.josm.gui.MainApplication"/>
     <stringAttribute key="org.eclipse.jdt.launching.MODULE_NAME" value="JOSM"/>
-    <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="--trace"/>
+    <stringAttribute key="org.eclipse.jdt.launching.PROGRAM_ARGUMENTS" value="--debug"/>
     <stringAttribute key="org.eclipse.jdt.launching.PROJECT_ATTR" value="JOSM"/>
     <stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-ea -Xverify:none"/>
 </launchConfiguration>