[TIKA-2392] Fix the rest of potential bugs and 2 new ones that may trigger NullPointerException + add test case

Author: longphan98

tika-app/src/main/java/org/apache/tika/gui/TikaGUI.java

@@ -610,7 +610,7 @@ public File requestSave(String embeddedName) throws IOException {
 
             int splitAt = embeddedName.lastIndexOf('.');
             if (splitAt > 0) {
-                embeddedName.substring(splitAt);
+                embeddedName = embeddedName.substring(splitAt);
             }
 
             File tmp = File.createTempFile("tika-embedded-", suffix);

tika-java7/src/test/java/org/apache/tika/filetypedetector/TikaFileTypeDetectorTest.java

@@ -47,9 +47,11 @@ public void setUp() throws Exception {
         testDirectory = tempDir;
         System.out.println(testDirectory.toAbsolutePath());
         try (InputStream is = this.getClass().getResourceAsStream(TEST_CLASSPATH)) {
+            assert is != null;
             Files.copy(is, testDirectory.resolve(TEST_HTML));
         }
         try (InputStream is = this.getClass().getResourceAsStream(TEST_CLASSPATH)) {
+            assert is != null;
             Files.copy(is, testDirectory.resolve(TEST_UNRECOGNISED_EXTENSION));
         }
     }

tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-ocr-module/src/main/java/org/apache/tika/parser/ocr/TesseractOCRConfig.java

@@ -410,7 +410,7 @@ public String getFilter() {
      *               Default value is triangle.
      */
     public void setFilter(String filter) {
-        if (filter.equals(null)) {
+        if (filter == null) {
             throw new IllegalArgumentException(
                     "Filter value cannot be null. Valid values are point, hermite, " +
                             "cubic, box, gaussian, catrom, triangle, quadratic and mitchell.");

tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-ocr-module/src/test/java/org/apache/tika/parser/ocr/TesseractOCRConfigTest.java

@@ -16,11 +16,6 @@
  */
 package org.apache.tika.parser.ocr;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
-
 import java.io.InputStream;
 import java.util.Arrays;
 import java.util.List;
@@ -31,6 +26,8 @@
 import org.apache.tika.config.TikaConfig;
 import org.apache.tika.parser.CompositeParser;
 
+import static org.junit.jupiter.api.Assertions.*;
+
 public class TesseractOCRConfigTest extends TikaTest {
 
     @Test
@@ -46,7 +43,7 @@ public void testNoConfig() throws Exception {
         assertEquals("gray", config.getColorspace(), "Invalid default colorpsace value");
         assertEquals("triangle", config.getFilter(), "Invalid default filter value");
         assertEquals(200, config.getResize(), "Invalid default resize value");
-        assertEquals(false, config.isApplyRotation(), "Invalid default applyRotation value");
+        assertFalse(config.isApplyRotation(), "Invalid default applyRotation value");
     }
 
     @Test
@@ -67,7 +64,7 @@ public void testPartialConfig() throws Exception {
         assertEquals(8, config.getDepth(), "Invalid overridden depth value");
         assertEquals("box", config.getFilter(), "Invalid overridden filter value");
         assertEquals(300, config.getResize(), "Invalid overridden resize value");
-        assertEquals(false, config.isApplyRotation(), "Invalid default applyRotation value");
+        assertFalse(config.isApplyRotation(), "Invalid default applyRotation value");
     }
 
     @Test
@@ -89,7 +86,7 @@ public void testFullConfig() throws Exception {
         assertEquals(8, config.getDepth(), "Invalid overridden depth value");
         assertEquals("box", config.getFilter(), "Invalid overridden filter value");
         assertEquals(300, config.getResize(), "Invalid overridden resize value");
-        assertEquals(true, config.isApplyRotation(), "Invalid default applyRotation value");
+        assertTrue(config.isApplyRotation(), "Invalid default applyRotation value");
     }
 
     @Test
@@ -250,6 +247,14 @@ public void testBadColorSpace() {
         });
     }
 
+    @Test
+    public void testNullFilter() {
+        TesseractOCRConfig config = new TesseractOCRConfig();
+        assertThrows(IllegalArgumentException.class, () -> {
+            config.setFilter(null);
+        });
+    }
+
     @Test
     public void testUpdatingConfigs() throws Exception {
         TesseractOCRConfig configA = new TesseractOCRConfig();