Make methods static. #1555

Fixes `MethodMayBeStatic` inspection violations.

Description:
>Reports any methods which may safely be made static. A method may be static if it is not synchronized, it does not reference any of its class' non static methods and non static fields and is not overridden in a sub class.

src/it/java/com/google/checkstyle/test/base/ConfigurationBuilder.java

@@ -37,7 +37,7 @@ public class ConfigurationBuilder extends BaseCheckTestSupport {
 		listFiles(files, ROOT, "java");
 	}
 
-	private Configuration getConfigurationFromXML(String aConfigName,
+	private static Configuration getConfigurationFromXML(String aConfigName,
 			Properties aProps) throws CheckstyleException {
 		try {
 			return ConfigurationLoader.loadConfiguration(aConfigName,

src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java

@@ -51,12 +51,12 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 @PrepareForTest({ ConfigurationLoader.class, ConfigurationLoaderTest.class })
 public class ConfigurationLoaderTest {
 
-    private Configuration loadConfiguration(String name)
+    private static Configuration loadConfiguration(String name)
         throws CheckstyleException {
         return loadConfiguration(name, new Properties());
     }
 
-    private Configuration loadConfiguration(
+    private static Configuration loadConfiguration(
         String name, Properties props) throws CheckstyleException {
         final String fName =
             "src/test/resources/com/puppycrawl/tools/checkstyle/configs/" + name;
@@ -213,7 +213,7 @@ public class ConfigurationLoaderTest {
             .containsKey("name.invalidPattern"));
     }
 
-    private void verifyConfigNode(
+    private static void verifyConfigNode(
         DefaultConfiguration config, String name, int childrenLength,
         Properties atts) throws Exception {
         assertEquals("name.", name, config.getName());
@@ -298,7 +298,7 @@ public class ConfigurationLoaderTest {
         }
     }
 
-    private Properties initProperties() {
+    private static Properties initProperties() {
         final Properties props = new Properties();
         props.put("a", "A");
         props.put("b", "B");

src/test/java/com/puppycrawl/tools/checkstyle/PackageNamesLoaderTest.java

@@ -61,7 +61,7 @@ public class PackageNamesLoaderTest {
         validatePackageNames(packageNames);
     }
 
-    private void validatePackageNames(Set<String> pkgNames) {
+    private static void validatePackageNames(Set<String> pkgNames) {
         final String[] checkstylePackages = {
             "com.puppycrawl.tools.checkstyle.",
             "com.puppycrawl.tools.checkstyle.checks.",

src/test/java/com/puppycrawl/tools/checkstyle/api/DetailASTTest.java

@@ -129,7 +129,7 @@ public class DetailASTTest {
         }
     }
 
-    private void checkFile(String filename) throws Exception {
+    private static void checkFile(String filename) throws Exception {
         final FileText text = new FileText(new File(filename),
                            System.getProperty("file.encoding", "UTF-8"));
         final FileContents contents = new FileContents(text);
@@ -139,7 +139,7 @@ public class DetailASTTest {
         }
     }
 
-    private void checkTree(final DetailAST node,
+    private static void checkTree(final DetailAST node,
                            final DetailAST parent,
                            final DetailAST prev,
                            final String filename,

src/test/java/com/puppycrawl/tools/checkstyle/api/FullIdentTest.java

@@ -24,7 +24,7 @@ import org.junit.Test;
 
 public class FullIdentTest {
 
-    public void testToString() {
+    public static void testToString() {
         DetailAST ast = new DetailAST();
         ast.setType(TokenTypes.LITERAL_NEW);
         ast.setColumnNo(14);

src/test/java/com/puppycrawl/tools/checkstyle/checks/UniquePropertiesCheckTest.java

@@ -114,7 +114,7 @@ public class UniquePropertiesCheckTest extends BaseFileSetCheckTestSupport {
      * @param file to be opened
      * @return detail message of {@link FileNotFoundException}
      */
-    private String getFileNotFoundDetail(File file) throws Exception {
+    private static String getFileNotFoundDetail(File file) throws Exception {
         // Create exception to know detail message we should wait in
         // LocalisedMessage
         try {

src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/FileTabCharacterCheckTest.java

@@ -96,7 +96,7 @@ public class FileTabCharacterCheckTest
      * Creates a configuration that is functionally close to that in the docs.
      * @param verbose verbose mode
      */
-    private DefaultConfiguration createConfig(boolean verbose) {
+    private static DefaultConfiguration createConfig(boolean verbose) {
         final DefaultConfiguration checkConfig =
             createCheckConfig(FileTabCharacterCheck.class);
         checkConfig.addAttribute("eachLine", Boolean.toString(verbose));

src/test/java/com/puppycrawl/tools/checkstyle/comments/CompareTreesWithComments.java

@@ -23,7 +23,7 @@ public class CompareTreesWithComments extends Check {
         Assert.assertTrue(isAstEquals(expectedTree, aRootAST));
     }
 
-    private boolean isAstEquals(DetailAST expected, DetailAST actual) {
+    private static boolean isAstEquals(DetailAST expected, DetailAST actual) {
         boolean result = false;
         if (expected == actual) {
             result = true;

src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWarningsFilterTest.java

@@ -116,7 +116,7 @@ public class SuppressWarningsFilterTest
         return checker;
     }
 
-    private String[] removeSuppressed(String[] from, String[] remove) {
+    private static String[] removeSuppressed(String[] from, String[] remove) {
         final Collection<String> coll =
             Lists.newArrayList(Arrays.asList(from));
         coll.removeAll(Arrays.asList(remove));

src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyCommentFilterTest.java

@@ -227,7 +227,7 @@ public class SuppressWithNearbyCommentFilterTest
         return checker;
     }
 
-    private String[] removeSuppressed(String[] from, String[] remove) {
+    private static String[] removeSuppressed(String[] from, String[] remove) {
         final Collection<String> coll =
             Lists.newArrayList(Arrays.asList(from));
         coll.removeAll(Arrays.asList(remove));

src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilterTest.java

@@ -227,7 +227,7 @@ public class SuppressionCommentFilterTest
         return checker;
     }
 
-    private String[] removeSuppressed(String[] from, String[] remove) {
+    private static String[] removeSuppressed(String[] from, String[] remove) {
         final Collection<String> coll =
             Lists.newArrayList(Arrays.asList(from));
         coll.removeAll(Arrays.asList(remove));