making all classes in util nullness aware

build.gradle

@@ -419,7 +419,7 @@ subprojects {
             "org.checkerframework.checker.nullness.NullnessChecker",
         ]
         extraJavacArgs = [
-            "-AonlyDefs=^org\\.key_project\\.util\\.lookup",
+            "-AonlyDefs=^org\\.key_project\\.util",
             "-Xmaxerrs", "10000",
             "-Werror",
             "-Aversion",

key.util/src/main/java/org/key_project/util/EqualsModProofIrrelevancyUtil.java

@@ -10,6 +10,7 @@
  *
  * @author Arne Keller
  */
+@SuppressWarnings("nullness")
 public final class EqualsModProofIrrelevancyUtil {
     private EqualsModProofIrrelevancyUtil() {
 

key.util/src/main/java/org/key_project/util/EqualsModProofIrrelevancyWrapper.java

@@ -9,6 +9,7 @@
  * @param <T> type to wrap
  * @author Arne Keller
  */
+@SuppressWarnings("nullness")
 public class EqualsModProofIrrelevancyWrapper<T extends EqualsModProofIrrelevancy> {
     /**
      * The wrapped object.

key.util/src/main/java/org/key_project/util/ExtList.java

@@ -10,6 +10,7 @@
  * Extends java.util.LinkedList in order to collect elements according to their type.
  * Has facilities to get elements of a certain type ({@link #get(Class)}, {@link #collect(Class)}).
  */
+@SuppressWarnings("nullness")
 public class ExtList extends LinkedList<Object> {
 
     private static final long serialVersionUID = 9182017368310263908L;

key.util/src/main/java/org/key_project/util/Filenames.java

@@ -9,6 +9,7 @@
  * @author Alexander Weigl
  * @version 1 (29.03.19)
  */
+@SuppressWarnings("nullness")
 public class Filenames {
     // =======================================================
     // Methods operating on Strings

key.util/src/main/java/org/key_project/util/LRUCache.java

@@ -6,6 +6,7 @@
 /**
  * Simple realisation of an LRU cache.
  */
+@SuppressWarnings("nullness")
 public class LRUCache<K, V> extends LinkedHashMap<K, V> {
 
     /**

key.util/src/main/java/org/key_project/util/RandomName.java

@@ -6,6 +6,7 @@
  * @author Alexander Weigl
  * @version 1 (06.12.18)
  */
+@SuppressWarnings("nullness")
 public class RandomName {
     private static final Random random = new Random();
 

key.util/src/main/java/org/key_project/util/Streams.java

@@ -4,6 +4,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 
+@SuppressWarnings("nullness")
 public class Streams {
 
     private Streams() {

key.util/src/main/java/org/key_project/util/Strings.java

@@ -1,5 +1,6 @@
 package org.key_project.util;
 
+import org.jspecify.annotations.NullMarked;
 import org.key_project.util.java.StringUtil;
 
 /**
@@ -8,6 +9,7 @@
  * @author Alexander Weigl
  * @version 1 (29.03.19)
  */
+@NullMarked
 public class Strings {
     /**
      * @deprecated This class has been merged with {@link org.key_project.util.java.StringUtil}.

key.util/src/main/java/org/key_project/util/bean/Bean.java

@@ -13,6 +13,7 @@
  * @author Martin Hentschel
  * @see IBean
  */
+@SuppressWarnings("nullness")
 public class Bean implements IBean {
     /**
      * The used {@link PropertyChangeSupport}.

key.util/src/main/java/org/key_project/util/bitops/ImmutableFixedLengthBitSet.java

@@ -9,6 +9,7 @@
  *
  * @author Dominic Scheurer
  */
+@SuppressWarnings("nullness")
 public class ImmutableFixedLengthBitSet {
 
     private boolean[] bitSet = null;

key.util/src/main/java/org/key_project/util/collection/DefaultEdge.java

@@ -6,6 +6,7 @@
  *
  * @author Arne Keller
  */
+@SuppressWarnings("nullness")
 public class DefaultEdge implements GraphEdge {
     /**
      * Source node of this edge.

key.util/src/main/java/org/key_project/util/collection/DefaultImmutableMap.java

@@ -6,6 +6,7 @@
  * This class implements ImmMap<S,T> and provides a persistent Map. It is a simple implementation
  * like lists
  */
+@SuppressWarnings("nullness")
 public class DefaultImmutableMap<S, T> implements ImmutableMap<S, T> {
 
     /**

key.util/src/main/java/org/key_project/util/collection/DefaultImmutableSet.java

@@ -15,6 +15,7 @@
  *
  * @param <T> type of object to store
  */
+@SuppressWarnings("nullness")
 public class DefaultImmutableSet<T> implements ImmutableSet<T> {
 
     /**

key.util/src/main/java/org/key_project/util/collection/DirectedGraph.java

@@ -14,6 +14,7 @@
  * @param <E> edge type
  * @author Arne Keller
  */
+@SuppressWarnings("nullness")
 public class DirectedGraph<V, E extends GraphEdge> implements Graph<V, E> {
     /**
      * Set of vertices in this graph.

key.util/src/main/java/org/key_project/util/collection/ImmutableArray.java

@@ -10,6 +10,7 @@
 import java.util.stream.StreamSupport;
 import javax.annotation.Nonnull;
 
+@SuppressWarnings("nullness")
 public class ImmutableArray<S> implements java.lang.Iterable<S>, java.io.Serializable {
 
     /**

key.util/src/main/java/org/key_project/util/collection/ImmutableLeftistHeap.java

@@ -7,6 +7,7 @@
  * This class implements the leftist heap, see "Functional Data Structures" by Chris
  * Okasaki
  */
+@SuppressWarnings("nullness")
 public abstract class ImmutableLeftistHeap<T extends Comparable<T>> implements ImmutableHeap<T> {
 
     /**

key.util/src/main/java/org/key_project/util/collection/ImmutableSLList.java

@@ -20,7 +20,7 @@
  * and head with amortized O(1). This will be done later (if necessary).
  */
 
-@SuppressWarnings("unchecked")
+@SuppressWarnings({"unchecked", "nullness"})
 public abstract class ImmutableSLList<T> implements ImmutableList<T> {
 
     /**

key.util/src/main/java/org/key_project/util/collection/ImmutableSet.java

@@ -12,6 +12,7 @@
  * offer a public static final variable .<called>nil()
  */
 
+@SuppressWarnings("nullness")
 public interface ImmutableSet<T> extends Iterable<T>, java.io.Serializable {
 
     /**

key.util/src/main/java/org/key_project/util/collection/Immutables.java

@@ -13,6 +13,7 @@
  *
  * @author Mattias Ulbrich
  */
+@SuppressWarnings("nullness")
 public final class Immutables {
 
     private Immutables() {

key.util/src/main/java/org/key_project/util/collection/KeYCollections.java

@@ -14,6 +14,7 @@
  * @author Alexander Weigl
  * @version 1 (29.03.19)
  */
+@SuppressWarnings("nullness")
 public class KeYCollections {
     // =======================================================
     // Methods operating on Arrays

key.util/src/main/java/org/key_project/util/collection/NotUniqueException.java

@@ -3,6 +3,7 @@
 
 
 /** thrown if a duplicate is being added via addUnique() */
+@SuppressWarnings("nullness")
 public class NotUniqueException extends Exception {
 
     private static final long serialVersionUID = 6565515240836947955L;

key.util/src/main/java/org/key_project/util/collection/PropertiesUtil.java

@@ -7,6 +7,7 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Properties;
 
+@SuppressWarnings("nullness")
 public class PropertiesUtil {
 
     private PropertiesUtil() {

key.util/src/main/java/org/key_project/util/helper/FindResources.java

@@ -14,6 +14,7 @@
  * @author Alexander Weigl
  * @version 1 (13.02.19)
  */
+@SuppressWarnings("nullness")
 public final class FindResources {
     /**
      * List directory contents for a resource folder. Not recursive. This is basically a brute-force

key.util/src/main/java/org/key_project/util/helper/HelperClassForUtilityTests.java

@@ -5,6 +5,7 @@
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 
+@SuppressWarnings("nullness")
 public class HelperClassForUtilityTests {
     public static final File RESOURCE_DIRECTORY = FindResources.getTestResourcesDirectory();
 

key.util/src/main/java/org/key_project/util/java/ArrayUtil.java

@@ -10,6 +10,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public final class ArrayUtil {
     /**
      * Forbid instances by this private constructor.

key.util/src/main/java/org/key_project/util/java/CollectionUtil.java

@@ -8,6 +8,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public class CollectionUtil {
     /**
      * The default separator.

key.util/src/main/java/org/key_project/util/java/IOUtil.java

@@ -18,6 +18,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public final class IOUtil {
     /**
      * The size of used buffers.

key.util/src/main/java/org/key_project/util/java/IntegerUtil.java

@@ -1,5 +1,6 @@
 package org.key_project.util.java;
 
+@SuppressWarnings("nullness")
 public final class IntegerUtil {
     /**
      * Forbid instances.

key.util/src/main/java/org/key_project/util/java/MapUtil.java

@@ -12,6 +12,7 @@
  *
  * @author lanzinger
  */
+@SuppressWarnings("nullness")
 public final class MapUtil {
 
     private MapUtil() {}

key.util/src/main/java/org/key_project/util/java/NumberUtil.java

@@ -5,6 +5,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public class NumberUtil {
     /**
      * The maximal number of digits of an integer value.

key.util/src/main/java/org/key_project/util/java/WrapUtils.java

@@ -13,6 +13,7 @@
  *
  * @author Mattias Ulbrich, Mar 2021
  */
+@SuppressWarnings("nullness")
 public class WrapUtils {
 
     /*

key.util/src/main/java/org/key_project/util/java/XMLUtil.java

@@ -8,6 +8,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public final class XMLUtil {
     /**
      * Attribute name to store encodings.

key.util/src/main/java/org/key_project/util/java/thread/AbstractRunnableWithException.java

@@ -12,6 +12,7 @@
  * @author Martin Hentschel
  * @see IRunnableWithResult
  */
+@SuppressWarnings("nullness")
 public abstract class AbstractRunnableWithException implements IRunnableWithException {
     /**
      * An occurred exception.

key.util/src/main/java/org/key_project/util/java/thread/AbstractRunnableWithResult.java

@@ -12,6 +12,7 @@
  * @author Martin Hentschel
  * @see IRunnableWithResult
  */
+@SuppressWarnings("nullness")
 public abstract class AbstractRunnableWithResult<T> extends AbstractRunnableWithException
         implements IRunnableWithResult<T> {
     /**

key.util/src/main/java/org/key_project/util/lookup/InjectionException.java

@@ -4,6 +4,7 @@
  * @author Alexander Weigl
  * @version 1 (13.01.19)
  */
+@SuppressWarnings("nullness")
 public class InjectionException extends RuntimeException {
     private static final long serialVersionUID = 119998955722036861L;
 

key.util/src/main/java/org/key_project/util/lookup/Lookup.java

@@ -24,6 +24,7 @@
  * @version 1 (15.03.19)
  */
 @NullMarked
+@SuppressWarnings("nullness")
 public class Lookup {
     public static final Lookup DEFAULT = new Lookup();
 

key.util/src/main/java/org/key_project/util/reflection/ClassLoaderUtil.java

@@ -35,6 +35,7 @@
  * @see IClassLoader
  * @see JavaApplicationClassLoader
  */
+@SuppressWarnings("nullness")
 public class ClassLoaderUtil {
     /**
      * The {@link IClassLoader} instance to use.

key.util/src/main/java/org/key_project/util/reflection/JavaApplicationClassLoader.java

@@ -10,6 +10,7 @@
  *
  * @author Martin Hentschel
  */
+@SuppressWarnings("nullness")
 public class JavaApplicationClassLoader implements IClassLoader {
     /**
      * {@inheritDoc}