diff --git a/animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/CheckSignatureMojo.java b/animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/CheckSignatureMojo.java
index 7ef2edca..7777d896 100644
--- a/animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/CheckSignatureMojo.java
+++ b/animal-sniffer-maven-plugin/src/main/java/org/codehaus/mojo/animal_sniffer/maven/CheckSignatureMojo.java
@@ -44,17 +44,21 @@
 import org.apache.maven.shared.artifact.filter.PatternIncludesArtifactFilter;
 import org.codehaus.mojo.animal_sniffer.ClassFileVisitor;
 import org.codehaus.mojo.animal_sniffer.ClassListBuilder;
+import org.codehaus.mojo.animal_sniffer.Clazz;
 import org.codehaus.mojo.animal_sniffer.SignatureChecker;
 import org.codehaus.plexus.util.StringUtils;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Checks the classes compiled by this module.
@@ -203,6 +207,8 @@ public void setSignature( String signatureId ) {
     @Component
     protected ArtifactFactory artifactFactory;
 
+    static Map<File, Map<String, Clazz>> classes = new ConcurrentHashMap<>();
+
     @Override
     public void execute()
         throws MojoExecutionException, MojoFailureException
@@ -262,7 +268,7 @@ public void execute()
             }
 
             final SignatureChecker signatureChecker =
-                new SignatureChecker( new FileInputStream( a.getFile() ), ignoredPackages,
+                new SignatureChecker( loadClasses( a.getFile() ), ignoredPackages,
                                       new MavenLogger( getLog() ) );
             signatureChecker.setCheckJars( false ); // don't want to decend into jar files that have been copied to
                                                     // the output directory as resources.
@@ -309,6 +315,17 @@ public void execute()
         }
     }
 
+    private static Map<String, Clazz> loadClasses( File f ) throws IOException
+    {
+        Map<String, Clazz> classes = CheckSignatureMojo.classes.get( f );
+        if ( classes == null )
+        {
+            classes = SignatureChecker.loadClasses( new FileInputStream( f ) );
+            CheckSignatureMojo.classes.putIfAbsent( f, classes );
+        }
+        return classes;
+    }
+
     private static Dependency findMatchingDependency( Signature signature, List<Dependency> dependencies )
     {
         Dependency match = null;
diff --git a/animal-sniffer/src/main/java/org/codehaus/mojo/animal_sniffer/SignatureChecker.java b/animal-sniffer/src/main/java/org/codehaus/mojo/animal_sniffer/SignatureChecker.java
index 82fc6ebe..7919ed23 100644
--- a/animal-sniffer/src/main/java/org/codehaus/mojo/animal_sniffer/SignatureChecker.java
+++ b/animal-sniffer/src/main/java/org/codehaus/mojo/animal_sniffer/SignatureChecker.java
@@ -74,7 +74,7 @@ public class SignatureChecker
      */
     public static final String PREVIOUS_ANNOTATION_FQN = "org.jvnet.animal_sniffer.IgnoreJRERequirement";
 
-    private final Map<String, Clazz> classes = new HashMap<>();
+    private final Map<String, Clazz> classes;
 
     private final Logger logger;
 
@@ -108,6 +108,13 @@ public static void main( String[] args )
     public SignatureChecker( InputStream in, Set<String> ignoredPackages, Logger logger )
         throws IOException
     {
+        this( loadClasses( in ), ignoredPackages, logger );
+    }
+
+    public SignatureChecker( Map<String, Clazz> classes, Set<String> ignoredPackages, Logger logger )
+        throws IOException
+    {
+        this.classes = classes;
         this.ignoredPackages = new HashSet<>();
         this.ignoredPackageRules = new LinkedList<>();
         for(String wildcard : ignoredPackages )
@@ -126,6 +133,11 @@ public SignatureChecker( InputStream in, Set<String> ignoredPackages, Logger log
         this.annotationDescriptors.add( toAnnotationDescriptor( PREVIOUS_ANNOTATION_FQN ) );
 
         this.logger = logger;
+    }
+
+    public static Map<String, Clazz> loadClasses( InputStream in ) throws IOException
+    {
+        Map<String, Clazz> classes = new HashMap<>();
         try (ObjectInputStream ois = new ObjectInputStream( new GZIPInputStream( in ) ))
         {
             while ( true )
@@ -133,7 +145,7 @@ public SignatureChecker( InputStream in, Set<String> ignoredPackages, Logger log
                 Clazz c = (Clazz) ois.readObject();
                 if ( c == null )
                 {
-                    return; // finished
+                    return classes; // finished
                 }
                 classes.put( c.getName(), c );
             }