RED-8359 - Migrate to gradle

.gitignore

@@ -27,3 +27,11 @@
 **/classpath-data.json
 **/dependencies-and-licenses-overview.txt
 git.tag
+
+gradle.properties
+gradlew
+gradlew.bat
+gradle/
+
+**/.gradle
+**/build

.gitlab-ci.yml

@@ -1,4 +1,5 @@
 include:
   - project: 'gitlab/gitlab'
     ref: 'main'
-    file: 'ci-templates/maven_deps.yml'
+    file: 'ci-templates/gradle_java.yml'
+

build.gradle.kts

@@ -0,0 +1,102 @@
+plugins {
+    `java-library`
+    `maven-publish`
+    `kotlin-dsl`
+    pmd
+    checkstyle
+    jacoco
+    id("io.freefair.lombok") version "8.4"
+    id("org.sonarqube") version "4.0.0.2929"
+}
+
+repositories {
+    mavenLocal()
+    maven {
+        url = uri("https://pdftron.com/maven/release")
+    }
+    maven {
+        url = uri("https://nexus.knecon.com/repository/gindev/");
+        credentials {
+            username = providers.gradleProperty("mavenUser").getOrNull();
+            password = providers.gradleProperty("mavenPassword").getOrNull();
+        }
+    }
+    mavenCentral()
+}
+
+dependencies {
+    api("org.projectlombok:lombok:1.18.30")
+    api("org.springframework.boot:spring-boot-configuration-processor:3.2.2")
+    api("com.google.guava:guava:33.0.0-jre")
+    api("com.pdftron:PDFNet:10.3.0")
+    testImplementation("org.junit.jupiter:junit-jupiter:5.10.2")
+    testImplementation("org.assertj:assertj-core:3.24.2")
+    testImplementation("org.mockito:mockito-core:5.2.0")
+    testImplementation("org.apache.logging.log4j:log4j-slf4j2-impl:2.22.1")
+    compileOnly("org.slf4j:slf4j-api:2.0.11")
+}
+
+group = "com.iqser.red.commons"
+description = "pdftron-logic-commons"
+java.sourceCompatibility = JavaVersion.VERSION_17
+java.targetCompatibility = JavaVersion.VERSION_17
+
+publishing {
+    publications {
+        create<MavenPublication>(name) {
+            from(components["java"])
+        }
+    }
+    repositories {
+        maven {
+            url = uri("https://nexus.knecon.com/repository/red-platform-releases/")
+            credentials {
+                username = providers.gradleProperty("mavenUser").getOrNull();
+                password = providers.gradleProperty("mavenPassword").getOrNull();
+            }
+        }
+    }
+}
+
+pmd {
+    isConsoleOutput = true
+}
+
+tasks.pmdMain {
+    pmd.ruleSetFiles = files("${rootDir}/config/pmd/pmd.xml")
+}
+
+tasks.pmdTest {
+    pmd.ruleSetFiles = files("${rootDir}/config/pmd/test_pmd.xml")
+}
+
+tasks.named<Test>("test") {
+    useJUnitPlatform()
+    reports {
+        junitXml.outputLocation.set(layout.buildDirectory.dir("reports/junit"))
+    }
+}
+
+sonarqube {
+    properties {
+        property("sonar.login", providers.gradleProperty("sonarToken").getOrNull())
+        property("sonar.host.url", "https://sonarqube.knecon.com")
+    }
+}
+
+tasks.test {
+    finalizedBy(tasks.jacocoTestReport)
+}
+
+tasks.jacocoTestReport {
+    dependsOn(tasks.test)
+    reports {
+        xml.required.set(true)
+        csv.required.set(false)
+        html.outputLocation.set(layout.buildDirectory.dir("jacocoHtml"))
+    }
+}
+
+java {
+    withJavadocJar()
+}

config/checkstyle/checkstyle.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+<module name="Checker">
+    <property
+            name="severity"
+            value="error"/>
+    <module name="TreeWalker">
+        <module name="SuppressWarningsHolder"/>
+        <module name="MissingDeprecated"/>
+        <module name="MissingOverride"/>
+        <module name="AnnotationLocation"/>
+        <module name="JavadocStyle"/>
+        <module name="NonEmptyAtclauseDescription"/>
+        <module name="IllegalImport"/>
+        <module name="RedundantImport"/>
+        <module name="RedundantModifier"/>
+        <module name="EmptyBlock"/>
+        <module name="DefaultComesLast"/>
+        <module name="EmptyStatement"/>
+        <module name="EqualsHashCode"/>
+        <module name="ExplicitInitialization"/>
+        <module name="IllegalInstantiation"/>
+        <module name="ModifiedControlVariable"/>
+        <module name="MultipleVariableDeclarations"/>
+        <module name="PackageDeclaration"/>
+        <module name="ParameterAssignment"/>
+        <module name="SimplifyBooleanExpression"/>
+        <module name="SimplifyBooleanReturn"/>
+        <module name="StringLiteralEquality"/>
+        <module name="OneStatementPerLine"/>
+        <module name="FinalClass"/>
+        <module name="ArrayTypeStyle"/>
+        <module name="UpperEll"/>
+        <module name="OuterTypeFilename"/>
+    </module>
+    <module name="FileTabCharacter"/>
+    <module name="SuppressWarningsFilter"/>
+</module>

config/pmd/pmd.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0"?>
+<ruleset name="Custom ruleset"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">
+
+    <description>
+        Knecon ruleset checks the code for bad stuff
+    </description>
+
+    <rule ref="category/java/errorprone.xml">
+        <exclude name="MissingSerialVersionUID"/>
+        <exclude name="AvoidLiteralsInIfCondition"/>
+        <exclude name="AvoidDuplicateLiterals"/>
+        <exclude name="NullAssignment"/>
+        <exclude name="AssignmentInOperand"/>
+        <exclude name="BeanMembersShouldSerialize"/>
+    </rule>
+
+</ruleset>

config/pmd/test_pmd.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0"?>
+<ruleset name="Custom ruleset"
+         xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 http://pmd.sourceforge.net/ruleset_2_0_0.xsd">
+
+    <description>
+        Knecon test ruleset checks the code for bad stuff
+    </description>
+
+
+    <rule ref="category/java/errorprone.xml">
+        <exclude name="MissingSerialVersionUID"/>
+        <exclude name="AvoidLiteralsInIfCondition"/>
+        <exclude name="AvoidDuplicateLiterals"/>
+        <exclude name="NullAssignment"/>
+        <exclude name="AssignmentInOperand"/>
+        <exclude name="TestClassWithoutTestCases"/>
+        <exclude name="BeanMembersShouldSerialize"/>
+    </rule>
+
+</ruleset>

gradle.properties.kts

@@ -0,0 +1 @@
+version = 2.0-SNAPSHOT

pom.xml

@@ -1,94 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
-         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-
-    <parent>
-        <artifactId>platform-dependency</artifactId>
-        <groupId>com.iqser.red</groupId>
-        <version>2.2.0</version>
-    </parent>
-
-    <modelVersion>4.0.0</modelVersion>
-
-    <properties>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    </properties>
-
-    <artifactId>pdftron-logic-commons</artifactId>
-    <groupId>com.iqser.red.commons</groupId>
-    <version>2.0-SNAPSHOT</version>
-
-
-    <dependencies>
-        <dependency>
-            <groupId>org.slf4j</groupId>
-            <artifactId>slf4j-api</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-slf4j2-impl</artifactId>
-            <version>2.20.0</version>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.guava</groupId>
-            <artifactId>guava</artifactId>
-        </dependency>
-
-        <dependency>
-            <groupId>com.pdftron</groupId>
-            <artifactId>PDFNet</artifactId>
-            <version>10.3.0</version>
-            <scope>provided</scope>
-        </dependency>
-        <!-- Test Dependencies -->
-    </dependencies>
-
-    <build>
-        <plugins>
-            <plugin>
-                <!-- create a test jar for the api classes to be used by other modules -->
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-jar-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <goals>
-                            <goal>test-jar</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-            <plugin>
-                <groupId>org.jacoco</groupId>
-                <artifactId>jacoco-maven-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>prepare-agent</id>
-                        <goals>
-                            <goal>prepare-agent</goal>
-                        </goals>
-                    </execution>
-                    <execution>
-                        <id>report</id>
-                        <goals>
-                            <goal>report</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-        </plugins>
-    </build>
-
-
-
-    <repositories>
-        <repository>
-            <id>pdftron</id>
-            <name>PDFNet Maven</name>
-            <url>https://pdftron.com/maven/release</url>
-        </repository>
-    </repositories>
-
-</project>

settings.gradle.kts

@@ -0,0 +1 @@
+rootProject.name = "pdftron-logic-commons"

src/main/java/com/iqser/red/pdftronlogic/commons/Converter.java

@@ -62,10 +62,9 @@ public class Converter {
     @SneakyThrows
     public static Color convertColor(ColorSpace colorSpace, ColorPt colorPt) {
 
-        ColorPt rgbColor = colorSpace.convert2RGB(colorPt);
+        try (ColorPt rgbColor = colorSpace.convert2RGB(colorPt)) {
-        Color color = new Color((float) rgbColor.get(0), (float) rgbColor.get(1), (float) rgbColor.get(2));
+            return new Color((float) rgbColor.get(0), (float) rgbColor.get(1), (float) rgbColor.get(2));
-        rgbColor.destroy();
+        }
-        return color;
     }
 
 

src/main/java/com/iqser/red/pdftronlogic/commons/ElementFeatures.java

@@ -103,6 +103,7 @@ public class ElementFeatures {
     @Getter
     @SuperBuilder
     @FieldDefaults(makeFinal = true, level = AccessLevel.PRIVATE)
+    @SuppressWarnings("PMD")
     public static class Text extends ElementFeatures {
 
         String text;

src/main/java/com/iqser/red/pdftronlogic/commons/ImageHashFactory.java

@@ -35,18 +35,17 @@ public class ImageHashFactory {
     @SneakyThrows
     private byte[] getBytesOfImage(com.pdftron.pdf.Image inputImage) {
         // 0 because the memory filter determines the size
-        var memFilter = new MemoryFilter(0, false);
+        try(var memFilter = new MemoryFilter(0, false);
-        var filterWriter = new FilterWriter(memFilter);
+            var filterWriter = new FilterWriter(memFilter)) {
 
             inputImage.export(filterWriter);
             filterWriter.flushAll();
             byte[] res = memFilter.getBuffer();
 
             memFilter.flushAll();
-        memFilter.destroy();
-        filterWriter.destroy();
             return res;
         }
+    }
 
 
     public String getSimplePHash(BufferedImage image) {

src/main/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalService.java

@@ -151,8 +151,8 @@ public class InvisibleElementRemovalService {
     private void execute(PDFDoc pdfDoc, boolean delta, boolean removePaths, Set<String> markedContentToIgnore) {
 
         log.info("Start removing invisible Elements");
-        ElementWriter writer = new ElementWriter();
+        try(ElementWriter writer = new ElementWriter();
-        ElementReader reader = new ElementReader();
+            ElementReader reader = new ElementReader()) {
             Set<Long> visitedXObjIds = new TreeSet<>();
 
             for (PageIterator iterator = pdfDoc.getPageIterator(); iterator.hasNext(); ) {
@@ -179,11 +179,8 @@ public class InvisibleElementRemovalService {
                 context.markedContentStack().clear();
 
                 removeOverlappedElements(page, writer, context);
-
             }
-        writer.destroy();
+        }
-        reader.destroy();
-
         log.info("Finished removing invisible Elements");
     }
 
@@ -239,7 +236,7 @@ public class InvisibleElementRemovalService {
 
     private void processImages(Element imageElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
 
-        Rect rect = imageElement.getBBox();
+        try(Rect rect = imageElement.getBBox()) {
 
             if (rect == null) {
                 return;
@@ -255,11 +252,12 @@ public class InvisibleElementRemovalService {
                 writer.writeElement(imageElement);
             }
         }
+    }
 
 
     private void processText(Element textElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
 
-        Rect textBBox = textElement.getBBox();
+        try(Rect textBBox = textElement.getBBox()) {
 
             if (textBBox == null) {
                 writer.writeElement(textElement);
@@ -304,6 +302,7 @@ public class InvisibleElementRemovalService {
                 }
             }
         }
+    }
 
 
     private void processForm(Element formElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
@@ -315,7 +314,7 @@ public class InvisibleElementRemovalService {
             context.visitedXObjIds().add(formObj.getObjNum());
             // writer needs to be newly initialized when entering a new content stream
             // see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
-            ElementWriter formWriter = new ElementWriter();
+            try(ElementWriter formWriter = new ElementWriter()) {
                 context.clippingPathStack().enterNewGState();
                 context.clippingPathStack().intersectClippingPath(new GeneralPath(Converter.toRectangle2D(formElement.getBBox())));
                 context.reader().formBegin();
@@ -326,11 +325,11 @@ public class InvisibleElementRemovalService {
 
                 processElements(formWriter, context);
                 formWriter.end();
-            formWriter.destroy();
                 context.reader().end();
                 context.clippingPathStack().leaveGState();
             }
         }
+    }
 
 
     private void processPath(Element pathElement, ElementWriter writer, InvisibleElementRemovalContext context) throws PDFNetException {
@@ -481,7 +480,7 @@ public class InvisibleElementRemovalService {
             context.visitedXObjIds().add(formObj.getObjNum());
             // writer needs to be newly initialized when entering a new content stream
             // see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
-            ElementWriter formWriter = new ElementWriter();
+            try(ElementWriter formWriter = new ElementWriter()) {
                 context.reader().formBegin();
                 formWriter.begin(formObj);
 
@@ -490,10 +489,10 @@ public class InvisibleElementRemovalService {
 
                 processOverlappedElements(formWriter, context);
                 formWriter.end();
-            formWriter.destroy();
                 context.reader().end();
             }
         }
+    }
 
 
     private boolean isTextRenderedVisibly(GState gState, Rect textBBox, InvisibleElementRemovalContext context) throws PDFNetException {
@@ -582,18 +581,16 @@ public class InvisibleElementRemovalService {
     @SneakyThrows
     private void drawBBox(ElementWriter writer, Rectangle2D r, String hexcolor) {
 
-        ColorPt colorPt = new ColorPt(Integer.valueOf(hexcolor.substring(1, 3), 16) / 255d,
+        try(ColorPt colorPt = new ColorPt(Integer.valueOf(hexcolor.substring(1, 3), 16) / 255d,
                 Integer.valueOf(hexcolor.substring(3, 5), 16) / 255d,
                 Integer.valueOf(hexcolor.substring(5, 7), 16) / 255d);
-        ElementBuilder eb = new ElementBuilder();
+            ElementBuilder eb = new ElementBuilder()) {
             Element rect = eb.createRect(r.getX(), r.getY(), r.getWidth(), r.getHeight());
             rect.setPathStroke(true);
             rect.getGState().setStrokeColorSpace(ColorSpace.createDeviceRGB());
             rect.getGState().setStrokeColor(colorPt);
             writer.writePlacedElement(rect);
-
+        }
-        colorPt.destroy();
-        eb.destroy();
     }
 
 

src/main/java/com/iqser/red/pdftronlogic/commons/MarkedContentStack.java

@@ -7,33 +7,33 @@ import java.util.Set;
 
 public class MarkedContentStack {
 
-    Deque<MarkedContent> markedContentStack = new LinkedList<>();
+    Deque<MarkedContent> stack = new LinkedList<>();
 
 
     public void enterMarkedContent(String name) {
 
-        markedContentStack.push(new MarkedContent(name));
+        stack.push(new MarkedContent(name));
     }
 
 
     public void leaveMarkedContent() {
 
-        markedContentStack.pop();
+        stack.pop();
     }
 
 
     public String currentMarkedContent() {
 
-        if (markedContentStack.isEmpty()) {
+        if (stack.isEmpty()) {
             return "";
         }
-        return markedContentStack.peek().name();
+        return stack.peek().name();
     }
 
 
     public boolean currentMarkedContentContains(String name) {
 
-        Iterator<MarkedContent> markedContentIterator = markedContentStack.descendingIterator();
+        Iterator<MarkedContent> markedContentIterator = stack.descendingIterator();
         while (markedContentIterator.hasNext()) {
             var markedContent = markedContentIterator.next();
             if (markedContent.name().equals(name)) {
@@ -46,10 +46,10 @@ public class MarkedContentStack {
 
     public boolean currentMarkedContentContainsAny(Set<String> names) {
 
-        if (markedContentStack.isEmpty()) {
+        if (stack.isEmpty()) {
             return false;
         }
-        Iterator<MarkedContent> markedContentIterator = markedContentStack.descendingIterator();
+        Iterator<MarkedContent> markedContentIterator = stack.descendingIterator();
         while (markedContentIterator.hasNext()) {
             var markedContent = markedContentIterator.next();
             if (names.contains(markedContent.name())) {
@@ -62,7 +62,7 @@ public class MarkedContentStack {
 
     public void clear() {
 
-        markedContentStack.clear();
+        stack.clear();
     }
 
 

src/main/java/com/iqser/red/pdftronlogic/commons/OCGWatermarkRemovalService.java

@@ -43,8 +43,8 @@ public class OCGWatermarkRemovalService {
     @SneakyThrows
     private void removeOCGWatermarks(PDFDoc pdfDoc) {
 
-        ElementReader reader = new ElementReader();
+        try(ElementReader reader = new ElementReader();
-        ElementWriter writer = new ElementWriter();
+            ElementWriter writer = new ElementWriter()) {
             Set<Long> visitedXObjIds = new TreeSet<>();
 
             for (PageIterator iterator = pdfDoc.getPageIterator(); iterator.hasNext(); ) {
@@ -52,9 +52,7 @@ public class OCGWatermarkRemovalService {
                 Page page = iterator.next();
                 writeAllElementsExceptWatermarks(page, reader, writer, visitedXObjIds);
             }
-
+        }
-        reader.destroy();
-        writer.destroy();
     }
 
 
@@ -124,7 +122,7 @@ public class OCGWatermarkRemovalService {
             visitedXObjIds.add(element.getXObject().getObjNum());
             // writer needs to be newly initialized when entering a new content stream
             // see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
-            ElementWriter formWriter = new ElementWriter();
+            try(ElementWriter formWriter = new ElementWriter()) {
                 reader.formBegin();
                 formWriter.begin(element.getXObject());
 
@@ -133,9 +131,9 @@ public class OCGWatermarkRemovalService {
 
                 processElements(page, reader, formWriter, visitedXObjIds);
                 formWriter.end();
-            formWriter.destroy();
                 reader.end();
             }
+        }
 
     }
 

src/main/java/com/iqser/red/pdftronlogic/commons/PdfTextExtraction.java

@@ -16,8 +16,8 @@ import lombok.experimental.UtilityClass;
 @UtilityClass
 public class PdfTextExtraction {
 
-    private static String execute(PDFDoc pdfDoc) throws IOException, PDFNetException{
+    private static String execute(PDFDoc pdfDoc) throws PDFNetException{
-        TextExtractor extractor = new TextExtractor();
+        try(TextExtractor extractor = new TextExtractor()) {
             List<String> texts = new ArrayList<>();
 
             PageIterator iterator = pdfDoc.getPageIterator();
@@ -27,10 +27,10 @@ public class PdfTextExtraction {
                 texts.add(extractor.getAsText());
             }
 
-        extractor.destroy();
             pdfDoc.close();
             return String.join("\n", texts);
         }
+    }
 
     public static String extractAllTextFromDocument(InputStream fileStream) throws IOException, PDFNetException {
         PDFDoc pdfDoc = new PDFDoc(fileStream);

src/main/java/com/iqser/red/pdftronlogic/commons/WatermarkRemovalService.java

@@ -93,7 +93,7 @@ public class WatermarkRemovalService {
         Map<Long, List<ElementFeatures>> formObjectsAndImagesForPages = new HashMap<>();
         Set<Long> visitedXObjIds = new TreeSet<>();
 
-        ElementReader reader = new ElementReader();
+        try(ElementReader reader = new ElementReader()) {
 
             for (PageIterator iterator = pdfDoc.getPageIterator(); iterator.hasNext(); ) {
 
@@ -111,10 +111,9 @@ public class WatermarkRemovalService {
                 formObjectsAndImagesForPages.put(page.getSDFObj().getObjNum(), elementFeaturesLinkedList);
             }
 
-        reader.destroy();
-
             return formObjectsAndImagesForPages;
         }
+    }
 
 
     private void processElement(Element element,
@@ -220,13 +219,13 @@ public class WatermarkRemovalService {
         }
 
         if (visitedXObjIds.add(element.getXObject().getObjNum())) {
-            ElementReader xObjectReader = new ElementReader();
+            try(ElementReader xObjectReader = new ElementReader()) {
                 xObjectReader.begin(element.getXObject());
                 for (Element element1 = xObjectReader.next(); element1 != null; element1 = xObjectReader.next()) {
                     processElement(element1, visitedXObjIds, elementFeaturesLinkedList, formObjectsOccuringMoreThanOnceOnAPage, minAreaCoveringPage, page);
                 }
                 elementFeaturesLinkedList.add(ElementFeatureFactory.extractFeatures(element));
-            xObjectReader.destroy();
+            }
         } else {
             elementFeaturesLinkedList.add(ElementFeatureFactory.extractFeatures(element));
         }
@@ -256,8 +255,8 @@ public class WatermarkRemovalService {
     @SneakyThrows
     private void removeAllWatermarks(PDFDoc pdfDoc, List<ElementFeatures> watermarksElementFeaturesList) {
 
-        ElementReader reader = new ElementReader();
+        try(ElementReader reader = new ElementReader();
-        ElementWriter writer = new ElementWriter();
+            ElementWriter writer = new ElementWriter()) {
             Set<Long> visitedXObjIds = new TreeSet<>();
 
             for (PageIterator iterator = pdfDoc.getPageIterator(); iterator.hasNext(); ) {
@@ -265,12 +264,8 @@ public class WatermarkRemovalService {
                 Page page = iterator.next();
 
                 writeAllElementsExceptWatermarks(page, reader, writer, watermarksElementFeaturesList, visitedXObjIds);
-
             }
-
+        }
-        reader.destroy();
-        writer.destroy();
-
     }
 
 
@@ -390,7 +385,7 @@ public class WatermarkRemovalService {
             visitedXObjIds.add(element.getXObject().getObjNum());
             // writer needs to be newly initialized when entering a new content stream
             // see ElementEditTest in PDFTron (https://www.pdftron.com/documentation/samples/android/java/ElementEditTest)
-            ElementWriter formWriter = new ElementWriter();
+            try(ElementWriter formWriter = new ElementWriter()) {
                 reader.formBegin();
                 formWriter.begin(element.getXObject());
 
@@ -399,9 +394,9 @@ public class WatermarkRemovalService {
 
                 processElements(page, reader, formWriter, watermarksElementFeaturesList, visitedXObjIds);
                 formWriter.end();
-            formWriter.destroy();
                 reader.end();
             }
+        }
 
     }
 

src/test/java/com/iqser/red/pdftronlogic/commons/InvisibleElementRemovalServiceTest.java

@@ -13,6 +13,7 @@ import com.pdftron.pdf.PDFNet;
 
 import lombok.SneakyThrows;
 
+@SuppressWarnings("PMD")
 class InvisibleElementRemovalServiceTest {
 
     InvisibleElementRemovalService invisibleElementRemovalService;

src/test/java/com/iqser/red/pdftronlogic/commons/WatermarkRemovalServiceTest.java

@@ -13,6 +13,7 @@ import com.pdftron.pdf.PDFNet;
 import lombok.SneakyThrows;
 
 @Disabled
+@SuppressWarnings("PMD")
 class WatermarkRemovalServiceTest {
 
     @SneakyThrows