diff --git a/org.eclipse.jdt.core.tests.builder/src/org/eclipse/jdt/core/tests/builder/BuildpathTests.java b/org.eclipse.jdt.core.tests.builder/src/org/eclipse/jdt/core/tests/builder/BuildpathTests.java
index 7fa9082..4b24418 100644
--- a/org.eclipse.jdt.core.tests.builder/src/org/eclipse/jdt/core/tests/builder/BuildpathTests.java
+++ b/org.eclipse.jdt.core.tests.builder/src/org/eclipse/jdt/core/tests/builder/BuildpathTests.java
@@ -448,6 +448,11 @@
 	fullBuild(projectPath);
 	expectingNoProblems();
 
+	if (Util.isMacOS()) {
+		// Wait a moment so the jar timestamp will be different
+		Thread.sleep(2000);
+	}
+
 	org.eclipse.jdt.core.tests.util.Util.createJar(
 		new String[] {
 			"p/X.java",
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/util/Util.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/util/Util.java
index b9f9454..c682c68 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/util/Util.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/util/Util.java
@@ -1073,6 +1073,7 @@
     return !file.exists() && getParentChildFile(file) == null;
 }
 public static boolean isMacOS() {
+	// Alternative: "macosx".equals(System.getProperty("osgi.os"))
     return System.getProperty("os.name").indexOf("Mac") != -1;
 }
 /**
diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClasspathTests.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClasspathTests.java
index 47aa1e2..3787075 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClasspathTests.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/ClasspathTests.java
@@ -3624,7 +3624,7 @@
 			JavaCore.VERSION_1_4);
 		createFile("/P/lib2.jar", "");
 		startDeltas();
-		if ("macosx".equals(System.getProperty("osgi.os"))) {
+		if (Util.isMacOS()) {
 			// necessary for filesystems with timestamps only upto seconds (eg. Mac)
 			// "lib1.jar" was created above and is modified below.
 			Thread.sleep(2000);