Backport from v4.5.3 release

Author: derjust

src/changes/changes.xml

@@ -39,6 +39,11 @@
         Added Spring 5 / Spring-Data Kay support
       </action>
     </release>
+    <release version="4.5.3" date="2017-01-14" description="Backport of PR #108">
+      <action dev="derjust" issue="108" type="fix" date="2018-01-14">
+        Opened constructor and fixed NPE in case of missing DynamoDBConfig
+      </action>
+    </release>
     <release version="4.5.2" date="2017-12-24" description="Backport of PR #106">
       <action dev="Gaurav Rawat" type="fix" issue="91">
         Fixed false assertion introduced implementing #91

src/main/java/org/socialsignin/spring/data/dynamodb/core/DynamoDBTemplate.java

@@ -43,14 +43,14 @@ public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB, DynamoDBMapperConfig dyna
 	    this(amazonDynamoDB, dynamoDBMapperConfig, null);
 	}
 
-	/** Convenient constructor to use the {@link DynamoDBMapperConfig.DEFAULT} */
+	/** Convenient constructor to use the {@link DynamoDBMapperConfig#DEFAULT} */
 
     public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB, DynamoDBMapper dynamoDBMapper)
     {
         this(amazonDynamoDB, null, dynamoDBMapper);
     }
 
-    /** Convenient construcotr to thse the {@link DynamoDBMapperConfig.DEFAULT} and default {@link DynamoDBMapper#DynamoDBMapper(AmazonDynamoDB)} */
+    /** Convenient construcotr to thse the {@link DynamoDBMapperConfig#DEFAULT} and default {@link DynamoDBMapper#DynamoDBMapper(AmazonDynamoDB)} */
     public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB)
     {
         this(amazonDynamoDB, null, null);
@@ -59,7 +59,7 @@ public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB)
     /** Initializes a new {@code DynamoDBTemplate}.
      * The following combinations are valid:
      * @param amazonDynamoDB must not be {@code null}
-     * @param dynamoDBMapperConfig can be {@code null} - {@link DynamoDBMapperConfig.DEFAULT} is used if {@code null} is passed in
+     * @param dynamoDBMapperConfig can be {@code null} - {@link DynamoDBMapperConfig#DEFAULT} is used if {@code null} is passed in
      * @param dynamoDBMapper can be {@code null} - {@link DynamoDBMapper#DynamoDBMapper(AmazonDynamoDB, DynamoDBMapperConfig)} is used if {@code null} is passed in */
 	public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB, DynamoDBMapperConfig dynamoDBMapperConfig, DynamoDBMapper dynamoDBMapper) {
        Assert.notNull(amazonDynamoDB, "amazonDynamoDB must not be null!");