diff --git a/spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/Context.java b/spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/Context.java
index 168e3d3148..f38364f883 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/Context.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/Context.java
@@ -55,7 +55,8 @@ class Context {
 	 * @param workingDir the working directory
 	 */
 	Context(File archiveFile, File workingDir) {
-		Assert.state(isExistingFile(archiveFile) && isJarOrWar(archiveFile), "Unable to find source archive");
+		Assert.state(isExistingFile(archiveFile), "Unable to find source archive");
+		Assert.state(isJarOrWar(archiveFile), "Source archive doesn't end with .jar or .war");
 		this.archiveFile = archiveFile;
 		this.workingDir = workingDir;
 		this.relativeDir = deduceRelativeDir(archiveFile.getParentFile(), this.workingDir);