diff --git a/org.eclipse.xtend.ide.tests/src/org/eclipse/xtend/ide/tests/compiler/QuickDebugSourceInstallingCompilationParticipantTest.java b/org.eclipse.xtend.ide.tests/src/org/eclipse/xtend/ide/tests/compiler/QuickDebugSourceInstallingCompilationParticipantTest.java
index e02e5ebbfab..8dadeb5d416 100644
--- a/org.eclipse.xtend.ide.tests/src/org/eclipse/xtend/ide/tests/compiler/QuickDebugSourceInstallingCompilationParticipantTest.java
+++ b/org.eclipse.xtend.ide.tests/src/org/eclipse/xtend/ide/tests/compiler/QuickDebugSourceInstallingCompilationParticipantTest.java
@@ -29,7 +29,6 @@
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.Opcodes;
 
-import com.google.common.io.ByteStreams;
 import com.google.inject.Inject;
 
 /**
@@ -66,12 +65,11 @@ def dosomething() {
 		final AtomicBoolean debugInfoFound = new AtomicBoolean(false);
 		Path classFile = clazz.getLocation().toPath();
 		try (var in = Files.newInputStream(classFile)) {
-			final byte[] bytes = ByteStreams.toByteArray(in);
-			final ClassReader r = new ClassReader(bytes);
+			final ClassReader r = new ClassReader(in);
 			r.accept(new ClassVisitor(Opcodes.ASM9) {
 				@Override
 				public void visitSource(final String source, final String debug) {
-					if ("Outer.java".equals(source)) {
+					if ("Outer.java".equals(source) && debug != null) {
 						assertEquals("""
 							SMAP
 							Outer.java
diff --git a/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/generator/trace/TraceForStorageProvider.java b/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/generator/trace/TraceForStorageProvider.java
index 0f60595a708..50030afb668 100644
--- a/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/generator/trace/TraceForStorageProvider.java
+++ b/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/generator/trace/TraceForStorageProvider.java
@@ -68,8 +68,8 @@ public AbsoluteURI getPath() {
 		}
 
 		@Override
-		public long getTimestamp() {
-			return file.getLocalTimeStamp();
+		public long getModificationStamp() {
+			return file.getModificationStamp();
 		}
 
 		@Override
diff --git a/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/internal/AbstractTraceForURIProvider.java b/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/internal/AbstractTraceForURIProvider.java
index bf50c5e4e6e..4e784e617b6 100644
--- a/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/internal/AbstractTraceForURIProvider.java
+++ b/org.eclipse.xtext/src/org/eclipse/xtext/generator/trace/internal/AbstractTraceForURIProvider.java
@@ -54,7 +54,7 @@ public abstract class AbstractTraceForURIProvider<SomeFile, Trace extends Abstra
 	
 	protected interface PersistedTrace {
 		AbsoluteURI getPath();
-		long getTimestamp();
+		long getModificationStamp();
 		InputStream openStream() throws IOException;
 		boolean exists();
 	}
@@ -69,7 +69,7 @@ private static class CacheKey {
 
 			public CacheKey(PersistedTrace source) {
 				this.path = source.getPath();
-				this.timestamp = source.getTimestamp();
+				this.timestamp = source.getModificationStamp();
 			}
 
 			@Override