Quality fixes and README.md update

Author: cardil

README.md

@@ -10,7 +10,7 @@ This classes shouldn't be used in any public API or library. It is designed to b
 
 ## Requirements
 
-* JDK >= 1.7
+* JDK >= 1.6
 
 ## Maven
 

src/main/java/pl/wavesoftware/eid/exceptions/Eid.java

@@ -93,6 +93,7 @@ public Eid(String id) {
      * @throws IllegalArgumentException if given format hasn't got two format specifiers <tt>"%s"</tt>, or if given format was
      * null
      */
+    @SuppressWarnings("UnusedReturnValue")
     public static String setMessageFormat(String format) {
         validateFormat(format, MESSAGE_FORMAT_NUM_SPEC);
         String oldFormat = Eid.messageFormat;

src/main/java/pl/wavesoftware/eid/utils/EidPreconditions.java

@@ -104,6 +104,7 @@
  * @since 0.1.0 (idea imported from Guava Library and COI code)
  * @author Krzysztof Suszyński <krzysztof.suszynski@wavesoftware.pl>
  */
+@SuppressWarnings("WeakerAccess")
 public final class EidPreconditions {
 
     protected EidPreconditions() {

src/main/scripts/sonar-incremental.sh

@@ -1,9 +1,9 @@
 #!/bin/sh
 unset MAVEN_OPTS
 unset JAVA_TOOL_OPTIONS
-exec mvn -Pci sonar:sonar \
-    -DskipTests \
-    -Dsonar.language=java \
-    -Dsonar.analysis.mode=incremental \
-    -Dsonar.host.url=https://sonar.wavesoftware.pl \
-    -Dsonar.preview.excludePlugins=buildstability,devcockpit,pdfreport,report,views,jira,buildbreaker,issueassign,scmstats
+exec mvn -P ci sonar:sonar \
+    -D skipTests \
+    -D sonar.language=java \
+    -D sonar.analysis.mode=incremental \
+    -D sonar.host.url=https://sonar.wavesoftware.pl \
+    -D sonar.preview.excludePlugins=buildstability,devcockpit,pdfreport,report,views,jira,buildbreaker,issueassign,scmstats

src/test/java/pl/wavesoftware/eid/exceptions/EidTest.java

@@ -26,10 +26,11 @@
  *
  * @author Krzysztof Suszyński <krzysztof.suszynski@wavesoftware.pl>
  */
+@SuppressWarnings({"ConstantConditions", "unused"})
 public class EidTest {
 
     @Rule
-    public ExpectedException thrown = ExpectedException.none();
+    public final ExpectedException thrown = ExpectedException.none();
 
     @Test
     public void testSetMessageFormat_Null() {

src/test/java/pl/wavesoftware/eid/exceptions/ExceptionsTest.java

@@ -31,6 +31,7 @@
  *
  * @author Krzysztof Suszyński <krzysztof.suszynski@wavesoftware.pl>
  */
+@SuppressWarnings("unused")
 @RunWith(Parameterized.class)
 public class ExceptionsTest {
 

src/test/java/pl/wavesoftware/eid/utils/EidPreconditionsTest.java

@@ -23,7 +23,6 @@
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
 import static org.hamcrest.Matchers.*;
-import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import static org.junit.internal.matchers.ThrowableMessageMatcher.hasMessage;
@@ -39,17 +38,14 @@
  *
  * @author Krzysztof Suszyński <krzysztof.suszynski@wavesoftware.pl>
  */
+@SuppressWarnings({"ConstantConditions", "unused"})
 public class EidPreconditionsTest {
 
     @Rule
-    public ExpectedException thrown = ExpectedException.none();
+    public final ExpectedException thrown = ExpectedException.none();
 
     private final String eid = "20150718:075046";
 
-    @Before
-    public void setUp() throws Exception {
-    }
-
     @Test
     public void testCheckArgument() {
         // given
@@ -227,8 +223,8 @@ public String execute() throws InterruptedIOException {
     public void testCreate() throws NoSuchMethodException {
         // given
         Class<EidPreconditions> cls = EidPreconditions.class;
-        Constructor<?> constr = cls.getDeclaredConstructor();
-        boolean access = constr.isAccessible();
+        Constructor<?> constructor = cls.getDeclaredConstructor();
+        boolean access = constructor.isAccessible();
 
         // then
         assertThat(access).isFalse();
@@ -237,6 +233,7 @@ public void testCreate() throws NoSuchMethodException {
 
             @Override
             public boolean matches(Object item) {
+                @SuppressWarnings("ThrowableResultOfMethodCallIgnored")
                 Eid eidObject = EidRuntimeException.class.cast(item).getEid();
                 return eidObject.getId().equals("20150718:083450")
                     && !eidObject.getRef().isEmpty()
@@ -406,6 +403,7 @@ public String execute() {
         assertThat(result).isEqualTo(tester);
     }
 
+    @SuppressWarnings("SameReturnValue")
     private Eid getNullEid() {
         return null;
     }