Merge pull request #8123 from eivinhb/7836_compile_with_empty_model

Fix for uncompilable java client if no model definitions is specified …

Author: HugoMario

modules/swagger-codegen/src/main/resources/Java/JSON.mustache

@@ -25,7 +25,9 @@ import org.threeten.bp.OffsetDateTime;
 import org.threeten.bp.format.DateTimeFormatter;
 {{/threetenbp}}
 
+{{#parent.length}}
 import {{modelPackage}}.*;
+{{/parent.length}}
 import okio.ByteString;
 
 import java.io.IOException;

modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/JSON.mustache

@@ -25,7 +25,9 @@ import org.threeten.bp.OffsetDateTime;
 import org.threeten.bp.format.DateTimeFormatter;
 {{/threetenbp}}
 
+{{#parent.length}}
 import {{modelPackage}}.*;
+{{/parent.length}}
 
 import java.io.IOException;
 import java.io.StringReader;