Java6 re-enabled

.travis.yml

@@ -1,2 +1,6 @@
 language: java
 sudo: false
+jdk:
+  - oraclejdk7
+  - oraclejdk8
+  - openjdk6

build.gradle

@@ -15,8 +15,8 @@ repositories {
     mavenCentral()
 }
 
-sourceCompatibility = 1.7
-targetCompatibility = 1.7
+sourceCompatibility = 1.6
+targetCompatibility = 1.6
 
 configurations.compile.transitive = false
 

src/test/java/com/hierynomus/sshj/userauth/method/AuthPasswordTest.java

@@ -139,7 +139,7 @@ public class AuthPasswordTest {
     }
 
     private static class StaticPasswordUpdateProvider implements PasswordUpdateProvider {
-        private Stack<String> newPasswords = new Stack<>();
+        private Stack<String> newPasswords = new Stack<String>();
 
         public StaticPasswordUpdateProvider(String... newPasswords) {
             for (int i = newPasswords.length - 1; i >= 0; i--) {