diff --git a/src/main/java/de/thetaphi/forbiddenapis/AbstractCheckMojo.java b/src/main/java/de/thetaphi/forbiddenapis/AbstractCheckMojo.java
index ff9d9783..5c1f5ddc 100644
--- a/src/main/java/de/thetaphi/forbiddenapis/AbstractCheckMojo.java
+++ b/src/main/java/de/thetaphi/forbiddenapis/AbstractCheckMojo.java
@@ -217,9 +217,18 @@ protected void logInfo(String msg) {
           log.info("Reading inline API signatures...");
           checker.parseSignaturesString(sig);
         }
-        if (bundledSignatures != null) for (String bs : bundledSignatures) {
-          log.info("Reading bundled API signatures: " + bs);
-          checker.parseBundledSignatures(bs, getTargetVersion());
+        if (bundledSignatures != null) {
+          String targetVersion = getTargetVersion();
+          if ("".equals(targetVersion)) targetVersion = null;
+          if (targetVersion == null) {
+            log.warn("The 'targetVersion' parameter or '${maven.compiler.target}' property is missing. " +
+              "Trying to read bundled JDK signatures without compiler target. " +
+              "You have to explicitely specify the version in the resource name.");
+          }
+          for (String bs : bundledSignatures) {
+            log.info("Reading bundled API signatures: " + bs);
+            checker.parseBundledSignatures(bs, targetVersion);
+          }
         }
         if (signaturesFiles != null) for (final File f : signaturesFiles) {
           log.info("Reading API signatures: " + f);
diff --git a/src/main/java/de/thetaphi/forbiddenapis/Checker.java b/src/main/java/de/thetaphi/forbiddenapis/Checker.java
index e13ae678..81e72924 100644
--- a/src/main/java/de/thetaphi/forbiddenapis/Checker.java
+++ b/src/main/java/de/thetaphi/forbiddenapis/Checker.java
@@ -295,7 +295,8 @@ public final void parseBundledSignatures(String name, String jdkTargetVersion) t
     InputStream in = this.getClass().getResourceAsStream("signatures/" + name + ".txt");
     // automatically expand the compiler version in here (for jdk-* signatures without version):
     if (in == null && jdkTargetVersion != null && name.startsWith("jdk-") && !name.matches(".*?\\-\\d\\.\\d")) {
-      in = this.getClass().getResourceAsStream("signatures/" + name + "-" + jdkTargetVersion + ".txt");
+      name = name + "-" + jdkTargetVersion;
+      in = this.getClass().getResourceAsStream("signatures/" + name + ".txt");
     }
     if (in == null) {
       throw new FileNotFoundException("Bundled signatures resource not found: " + name);
diff --git a/src/test/antunit/TestMavenMojo.xml b/src/test/antunit/TestMavenMojo.xml
index 838cd5e6..bfe36bd8 100644
--- a/src/test/antunit/TestMavenMojo.xml
+++ b/src/test/antunit/TestMavenMojo.xml
@@ -66,6 +66,18 @@
     <au:assertLogContains text="The class 'foo.bar.ForbiddenApis' referenced in a signature cannot be loaded, ignoring signature: foo.bar.ForbiddenApis#testMethod()"/> 
   </target>
   
+  <target name="testMissingTargetVersion">
+    <au:expectfailure>
+      <artifact:mvn pom="${antunit.fake-pom}" mavenVersion="${maven.version}" failonerror="true" fork="true">
+        <arg value="${groupId}:${artifactId}:${version}:check"/>
+        <syspropertyset refid="injected-properties"/>
+        <sysproperty key="maven.compiler.target" value=""/>
+      </artifact:mvn>
+    </au:expectfailure>
+    <au:assertLogContains text="The 'targetVersion' parameter or '${maven.compiler.target}' property is missing."/> 
+    <au:assertLogContains text="Bundled signatures resource not found"/> 
+  </target>
+  
   <target name="testMyselfMaven3">
     <artifact:mvn pom="${antunit.fake-pom}" mavenVersion="${antunit.maven3.version}" failonerror="true" fork="true">
       <arg value="${groupId}:${artifactId}:${version}:check"/>