Merge some string literals

Author: garydgregory

src/main/java/org/apache/commons/pool2/PoolUtils.java

@@ -86,7 +86,7 @@ private long getNextShrink() {
          */
         @Override
         public String toString() {
-            return "ErodingFactor{" + "factor=" + factor +
+            return "ErodingFactor{factor=" + factor +
                     ", idleHighWaterMark=" + idleHighWaterMark + '}';
         }
 
@@ -323,7 +323,7 @@ public void returnObject(final K key, final V obj) throws Exception {
          */
         @Override
         public String toString() {
-            return "ErodingKeyedObjectPool{" + "factor=" +
+            return "ErodingKeyedObjectPool{factor=" +
                     erodingFactor + ", keyedPool=" + keyedPool + '}';
         }
     }
@@ -465,7 +465,7 @@ public void returnObject(final T obj) {
          */
         @Override
         public String toString() {
-            return "ErodingObjectPool{" + "factor=" + factor + ", pool=" +
+            return "ErodingObjectPool{factor=" + factor + ", pool=" +
                     pool + '}';
         }
     }
@@ -515,7 +515,7 @@ protected ErodingFactor getErodingFactor(final K key) {
         @SuppressWarnings("resource") // getKeyedPool(): ivar access
         @Override
         public String toString() {
-            return "ErodingPerKeyKeyedObjectPool{" + "factor=" + factor +
+            return "ErodingPerKeyKeyedObjectPool{factor=" + factor +
                     ", keyedPool=" + getKeyedPool() + '}';
         }
     }

src/test/java/org/apache/commons/pool2/WaiterFactory.java

@@ -158,10 +158,8 @@ public PooledObject<Waiter> makeObject(final K key) {
         synchronized (this) {
             activeCounts.merge(key, ONE, (v1, v2) -> {
                 if (v1.intValue() >= maxActivePerKey) {
-                    throw new IllegalStateException("Too many active " +
-                    "instances for key = " + key + ": " + v1.intValue() +
-                    " in circulation " + "with maxActivePerKey = " +
-                    maxActivePerKey);
+                    throw new IllegalStateException("Too many active instances for key = " + key + ": " + v1.intValue()
+                            + " in circulation with maxActivePerKey = " + maxActivePerKey);
                 }
                 return Integer.valueOf(v1.intValue() + 1);
             });