diff --git a/src/main/java/com/r35157/libs/random/impl/ref/RandomValueGeneratorStringImpl.java b/src/main/java/com/r35157/libs/random/impl/ref/RandomValueGeneratorStringImpl.java
index 519a7a3..661720e 100644
--- a/src/main/java/com/r35157/libs/random/impl/ref/RandomValueGeneratorStringImpl.java
+++ b/src/main/java/com/r35157/libs/random/impl/ref/RandomValueGeneratorStringImpl.java
@@ -4,12 +4,19 @@ import com.r35157.libs.random.RandomValueGeneratorInt;
 import com.r35157.libs.random.RandomValueGeneratorString;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Objects;
+
 public class RandomValueGeneratorStringImpl implements RandomValueGeneratorString {
     public RandomValueGeneratorStringImpl(@NotNull RandomValueGeneratorInt rvgi) {
+        Objects.requireNonNull(rvgi, "Cannot initialize with <null> RandomValueGeneratorInt!");
         this.rvgi = rvgi;
     }
 
-    public @NotNull String getSomeStringAlphaNumericOnly(int length) {
+    public @NotNull String getSomeStringAlphaNumericOnly(int length) throws IllegalArgumentException {
+        if(length < 0) {
+            throw new IllegalArgumentException("Cannot generate random Strings of size " + length + "!");
+        }
+
         //             ASCII        Range size
         // Numeric     48-57        10
         // Alpha upper 65-90        26