diff --git a/src/main/java/org/apache/commons/logging/impl/AvalonLogger.java b/src/main/java/org/apache/commons/logging/impl/AvalonLogger.java
index c0ee68e..b95cdad 100644
--- a/src/main/java/org/apache/commons/logging/impl/AvalonLogger.java
+++ b/src/main/java/org/apache/commons/logging/impl/AvalonLogger.java
@@ -17,6 +17,8 @@
 
 package org.apache.commons.logging.impl;
 
+import java.util.Objects;
+
 import org.apache.avalon.framework.logger.Logger;
 import org.apache.commons.logging.Log;
 
@@ -73,9 +75,7 @@ public class AvalonLogger implements Log {
      * @param name the name of the avalon logger implementation to delegate to
      */
     public AvalonLogger(final String name) {
-        if (defaultLogger == null) {
-            throw new NullPointerException("default logger has to be specified if this constructor is used!");
-        }
+        Objects.requireNonNull(defaultLogger, "default logger has to be specified if this constructor is used!");
         this.logger = defaultLogger.getChildLogger(name);
     }
 
diff --git a/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java b/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
index f8a21df..a168581 100644
--- a/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
+++ b/src/main/java/org/apache/commons/logging/impl/WeakHashtable.java
@@ -26,6 +26,7 @@ import java.util.HashSet;
 import java.util.Hashtable;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
 /**
@@ -228,12 +229,8 @@ public final class WeakHashtable extends Hashtable {
     @Override
     public synchronized Object put(final Object key, final Object value) {
         // check for nulls, ensuring semantics match superclass
-        if (key == null) {
-            throw new NullPointerException("Null keys are not allowed");
-        }
-        if (value == null) {
-            throw new NullPointerException("Null values are not allowed");
-        }
+        Objects.requireNonNull(key, "key");
+        Objects.requireNonNull(value, "value");
 
         // for performance reasons, only purge every
         // MAX_CHANGES_BEFORE_PURGE times