Fix code quality issues

sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/fs/internal/DefaultIndexedFile.java

@@ -126,7 +126,7 @@ public class DefaultIndexedFile extends DefaultInputComponent implements Indexed
       return true;
     }
 
-    if (!(o instanceof DefaultIndexedFile)) {
+    if (o == null || o.getClass() != this.getClass()) {
       return false;
     }
 

sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/fs/internal/DefaultTextPointer.java

@@ -51,7 +51,7 @@ public class DefaultTextPointer implements TextPointer {
 
   @Override
   public boolean equals(Object obj) {
-    if (!(obj instanceof DefaultTextPointer)) {
+    if (obj == null || obj.getClass() != this.getClass()) {
       return false;
     }
     DefaultTextPointer other = (DefaultTextPointer) obj;

sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/fs/internal/DefaultTextRange.java

@@ -59,7 +59,7 @@ public class DefaultTextRange implements TextRange {
 
   @Override
   public boolean equals(Object obj) {
-    if (!(obj instanceof DefaultTextRange)) {
+    if (obj == null || obj.getClass() != this.getClass()) {
       return false;
     }
     DefaultTextRange other = (DefaultTextRange) obj;

sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/fs/internal/TestInputFileBuilder.java

@@ -86,10 +86,10 @@ public class TestInputFileBuilder {
    * filePath must point to a file that is within the module base directory.
    */
   public TestInputFileBuilder(String projectKey, File moduleBaseDir, File filePath) {
-    String relativePath = moduleBaseDir.toPath().relativize(filePath.toPath()).toString();
+    String relativePathStr = moduleBaseDir.toPath().relativize(filePath.toPath()).toString();
     this.projectKey = projectKey;
     setModuleBaseDir(moduleBaseDir.toPath());
-    this.relativePath = PathUtils.sanitize(relativePath);
+    this.relativePath = PathUtils.sanitize(relativePathStr);
     this.id = batchId++;
   }
 

sonar-plugin-api-impl/src/main/java/org/sonar/api/batch/sensor/internal/DefaultStorable.java

@@ -28,8 +28,8 @@ import static org.sonar.api.utils.Preconditions.checkState;
 
 public abstract class DefaultStorable {
 
-  protected final transient SensorStorage storage;
-  private transient boolean saved = false;
+  protected final SensorStorage storage;
+  private boolean saved = false;
 
   public DefaultStorable() {
     this.storage = null;

sonar-plugin-api-impl/src/main/java/org/sonar/api/impl/ws/ValidatingRequest.java

@@ -85,6 +85,9 @@ public abstract class ValidatingRequest extends Request {
   @Override
   public List<String> multiParam(String key) {
     WebService.Param definition = action.param(key);
+    if (definition == null) {
+      throw new IllegalArgumentException("Parameter '" + key + "' not found for action '" + action.key() + "'");
+    }
     List<String> values = readMultiParamOrDefaultValue(key, definition);
     return validateValues(values, definition);
   }
@@ -224,7 +227,7 @@ public abstract class ValidatingRequest extends Request {
     checkArgument(valueAsInt <= maximumValue, "'%s' value (%s) must be less than %s", key, valueAsInt, maximumValue);
   }
 
-  private static void validateRequiredValue(String key, WebService.Param definition, String value) {
+  private static void validateRequiredValue(String key, WebService.Param definition, @Nullable String value) {
     boolean required = definition.isRequired();
     if (required) {
       checkArgument(value != null, format(MSG_PARAMETER_MISSING, key));

sonar-plugin-api/src/test/java/org/sonar/api/server/ws/RequestTest.java

@@ -591,7 +591,7 @@ public class RequestTest {
   @Test
   public void fail_if_multi_param_is_not_defined() {
     expectedException.expect(IllegalArgumentException.class);
-    expectedException.expectMessage("BUG - parameter 'unknown' is undefined for action 'my_action'");
+    expectedException.expectMessage("Parameter 'unknown' not found for action 'my_action'");
 
     underTest.multiParam("unknown");
   }