public boolean isEmpty (){
         if(hashCount == 0){
             return true;
         }
         return false;
     }

public boolean isEmpty (){
         return hashCount == 0;
     }

beide Strings muessen nicht leer sein!

public void getList(String matNr){
         System.out.println(theLists[myhash(matNr)]);    
     }

if(matNr == "" || name == "")

class Entry<K,V> {
    public final K key;
    public final V value;

    public Entry(K key, V, value) {
        this.key = key;
        this.value = value;
    }
}

public String giveName (String matNr) {
    // use hash to get the correct bucket
    List<Entry<String, String>> whichList = theLists[myhash(matNr)];

    // see if this bucket has a entry with the given key and return if found
    for(Entry<String, String> entry : whichList) {
        if(matNr.equals(entry.key)) {
            return entry.value;
        }
    }
    // fall throught if nothing is found
    return null;
}