diff --git a/sootup.core/src/main/java/sootup/core/cache/ClassCache.java b/sootup.core/src/main/java/sootup/core/cache/ClassCache.java
index 27674076559..9ff63ae4651 100644
--- a/sootup.core/src/main/java/sootup/core/cache/ClassCache.java
+++ b/sootup.core/src/main/java/sootup/core/cache/ClassCache.java
@@ -24,20 +24,37 @@
 
 import java.util.Collection;
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import sootup.core.frontend.SootClassSource;
 import sootup.core.model.SootClass;
 import sootup.core.types.ClassType;
 
 /** Interface for different caching strategies of resolved classes. */
-public interface ClassCache {
+public interface ClassCache<C extends SootClass> {
 
-  SootClass getClass(ClassType classType);
+  /**
+   * return the SootClass identified by classType
+   * */
+  C getClass(@Nonnull ClassType classType);
 
+  /**
+   * return all SootClasses stored in this Cache
+   * */
   @Nonnull
-  Collection<SootClass> getClasses();
-
-  void putClass(ClassType classType, SootClass sootClass);
-
-  boolean hasClass(ClassType classType);
+  Collection<C> getClasses();
+
+  /**
+   * add the given SootClass into the Cache
+   * */
+  // TODO: simplify: classType can be retrieved from sootClass.getType()
+  @Nullable
+  C putClass(@Nonnull ClassType classType, @Nonnull C sootClass);
+
+  /**
+   * Check if the associated SootClass for ClassType exists in the Cache
+   * */
+  boolean hasClass(@Nonnull ClassType classType);
 
   int size();
 }
diff --git a/sootup.core/src/main/java/sootup/core/cache/FullCache.java b/sootup.core/src/main/java/sootup/core/cache/FullCache.java
index f1932077315..852bd645940 100644
--- a/sootup.core/src/main/java/sootup/core/cache/FullCache.java
+++ b/sootup.core/src/main/java/sootup/core/cache/FullCache.java
@@ -30,28 +30,28 @@
 import sootup.core.types.ClassType;
 
 /** Cache that stores any class that has been resolved. */
-public class FullCache implements ClassCache {
+public class FullCache<C extends SootClass> implements ClassCache<C> {
 
-  protected final Map<ClassType, SootClass> cache = new HashMap<>();
+  protected final Map<ClassType, C> cache = new HashMap<>();
 
   @Override
-  public synchronized SootClass getClass(ClassType classType) {
+  public synchronized C getClass(@Nonnull ClassType classType) {
     return cache.get(classType);
   }
 
   @Nonnull
   @Override
-  public synchronized Collection<SootClass> getClasses() {
+  public synchronized Collection<C> getClasses() {
     return cache.values();
   }
 
   @Override
-  public void putClass(ClassType classType, SootClass sootClass) {
-    cache.putIfAbsent(classType, sootClass);
+  public C putClass(@Nonnull ClassType classType, @Nonnull C sootClass) {
+    return cache.putIfAbsent(classType, sootClass);
   }
 
   @Override
-  public boolean hasClass(ClassType classType) {
+  public boolean hasClass(@Nonnull ClassType classType) {
     return cache.containsKey(classType);
   }
 
diff --git a/sootup.core/src/main/java/sootup/core/cache/LRUCache.java b/sootup.core/src/main/java/sootup/core/cache/LRUCache.java
index 3f327d99a56..aafd404db03 100644
--- a/sootup.core/src/main/java/sootup/core/cache/LRUCache.java
+++ b/sootup.core/src/main/java/sootup/core/cache/LRUCache.java
@@ -31,37 +31,38 @@
  * Cache that implements a least recently used strategy. If the amount of stored classes exceeds a
  * specified amount, the lest recently used class will be overwritten.
  */
-public class LRUCache implements ClassCache {
-  private final LinkedHashMap<ClassType, SootClass> cache;
+public class LRUCache<C extends SootClass> implements ClassCache<C> {
+
+  @Nonnull private final LinkedHashMap<ClassType, C> cache;
 
   public LRUCache(int cacheSize) {
     cache =
-        new LinkedHashMap<ClassType, SootClass>(cacheSize, 1, true) {
+        new LinkedHashMap<ClassType, C>(cacheSize, 1, true) {
           @Override
-          protected boolean removeEldestEntry(Map.Entry<ClassType, SootClass> eldest) {
+          protected boolean removeEldestEntry(Map.Entry<ClassType, C> eldest) {
             return size() > cacheSize;
           };
         };
   }
 
   @Override
-  public synchronized SootClass getClass(ClassType classType) {
+  public synchronized C getClass(@Nonnull ClassType classType) {
     return cache.get(classType);
   }
 
   @Nonnull
   @Override
-  public synchronized Collection<SootClass> getClasses() {
+  public synchronized Collection<C> getClasses() {
     return cache.values();
   }
 
   @Override
-  public void putClass(ClassType classType, SootClass sootClass) {
-    cache.putIfAbsent(classType, sootClass);
+  public C putClass(@Nonnull ClassType classType, @Nonnull C sootClass) {
+    return cache.putIfAbsent(classType, sootClass);
   }
 
   @Override
-  public boolean hasClass(ClassType classType) {
+  public boolean hasClass(@Nonnull ClassType classType) {
     return cache.containsKey(classType);
   }
 
diff --git a/sootup.core/src/main/java/sootup/core/cache/MutableClassCache.java b/sootup.core/src/main/java/sootup/core/cache/MutableClassCache.java
index c4d1435e1ca..16bb440d1ff 100644
--- a/sootup.core/src/main/java/sootup/core/cache/MutableClassCache.java
+++ b/sootup.core/src/main/java/sootup/core/cache/MutableClassCache.java
@@ -27,11 +27,11 @@
 import sootup.core.types.ClassType;
 
 /** Interface for caches which are mutable and allow classes to be removed from. */
-public interface MutableClassCache extends ClassCache {
+public interface MutableClassCache<C extends SootClass> extends ClassCache<C> {
   SootClass removeClass(ClassType classType);
 
   default SootClass replaceClass(
-      @Nonnull ClassType oldType, @Nonnull ClassType newType, @Nonnull SootClass newClass) {
+      @Nonnull ClassType oldType, @Nonnull ClassType newType, @Nonnull C newClass) {
     SootClass oldClass = removeClass(oldType);
     putClass(newType, newClass);
     return oldClass;
diff --git a/sootup.core/src/main/java/sootup/core/cache/MutableFullCache.java b/sootup.core/src/main/java/sootup/core/cache/MutableFullCache.java
index e03b8512724..a22c82ac1e8 100644
--- a/sootup.core/src/main/java/sootup/core/cache/MutableFullCache.java
+++ b/sootup.core/src/main/java/sootup/core/cache/MutableFullCache.java
@@ -23,6 +23,8 @@
  */
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import sootup.core.model.SootClass;
 import sootup.core.types.ClassType;
 
@@ -30,8 +32,20 @@
  * Mutable version of the {@link FullCache} that additionally allows for a removal of cached
  * classes.
  */
-public class MutableFullCache extends FullCache implements MutableClassCache {
+public class MutableFullCache<C extends SootClass> extends FullCache<C> implements MutableClassCache<C> {
+
+  /**
+   * set SootClass into Cache, if element exists it will be replaced.
+   * */
+  @Override
+  @Nullable
+  public C putClass(@Nonnull ClassType classType, @Nonnull C sootClass) {
+    return cache.put(classType, sootClass);
+  }
 
+  /**
+   * removes the SootClass identified by classType from the Cache.
+   * */
   @Override
   public SootClass removeClass(@Nonnull ClassType classType) {
     if (this.hasClass(classType)) {