switch to Java 21 for build/Docker (#4759)

fixes #4459

Author: vladak

.github/workflows/build.yml

@@ -11,7 +11,7 @@ on:
 
 jobs:
   build:
-    name: ${{ matrix.os }} with Java 17
+    name: ${{ matrix.os }} with Java 21
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
@@ -22,11 +22,11 @@ jobs:
       uses: actions/checkout@v4
       with:
         fetch-depth: 0
-    - name: Set up JDK 17
+    - name: Set up JDK
       uses: actions/setup-java@v4
       with:
         distribution: 'oracle'
-        java-version: '17'
+        java-version: '21'
     - name: Cache Maven packages
       uses: actions/cache@v4
       with:

.github/workflows/javadoc.yml

@@ -18,11 +18,11 @@ jobs:
     steps:
     - name: Checkout master branch
       uses: actions/checkout@v4
-    - name: Set up JDK 17
+    - name: Set up JDK
       uses: actions/setup-java@v4
       with:
         distribution: 'oracle'
-        java-version: '17'
+        java-version: '21'
     - name: Cache Maven packages
       uses: actions/cache@v4
       with:

.github/workflows/release.yml

@@ -25,11 +25,11 @@ jobs:
     steps:
     - name: Checkout master branch
       uses: actions/checkout@v4
-    - name: Set up JDK 17
+    - name: Set up JDK
       uses: actions/setup-java@v4
       with:
         distribution: 'oracle'
-        java-version: '17'
+        java-version: '21'
     - name: Cache Maven packages
       uses: actions/cache@v4
       with:

Dockerfile

@@ -1,10 +1,10 @@
-# Copyright (c) 2018, 2024 Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2018, 2025 Oracle and/or its affiliates. All rights reserved.
 # Portions Copyright (c) 2020, Chris Fraire <cfraire@me.com>.
 
 FROM ubuntu:jammy AS build
 
 # hadolint ignore=DL3008
-RUN apt-get update && apt-get install --no-install-recommends -y openjdk-17-jdk python3 python3-venv && \
+RUN apt-get update && apt-get install --no-install-recommends -y openjdk-21-jdk python3 python3-venv && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
@@ -41,7 +41,7 @@ RUN cp `ls -t distribution/target/*.tar.gz | head -1` /opengrok.tar.gz
 # Store the version in a file so that the tools can report it.
 RUN /mvn/mvnw help:evaluate -Dexpression=project.version -q -DforceStdout > /mvn/VERSION
 
-FROM tomcat:10.1.40-jdk17
+FROM tomcat:10.1.40-jdk21
 LABEL maintainer="https://github.com/oracle/opengrok"
 LABEL org.opencontainers.image.source="https://github.com/oracle/opengrok"
 LABEL org.opencontainers.image.description="OpenGrok code search"

docker/README.md

@@ -26,7 +26,7 @@ image based on the official one.
 ## Additional info about the image
 
 * Tomcat 10
-* JRE 17
+* JRE 21
 * Configurable mirroring/reindexing (default every 10 min)
 
 The mirroring step works by going through all projects and attempting to

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/Definitions.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2008, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2025, Oracle and/or its affiliates. All rights reserved.
  * Portions Copyright (c) 2018, Chris Fraire <cfraire@me.com>.
  */
 package org.opengrok.indexer.analysis;
@@ -66,24 +66,24 @@ public static class LineTagMap implements Serializable {
 
         private static final long serialVersionUID = 1191703801007779481L;
         @SuppressWarnings("java:S116")
-        private final Map<String, Set<Tag>> sym_tags; //NOPMD
+        private final HashMap<String, Set<Tag>> sym_tags; //NOPMD
 
         protected LineTagMap() {
             this.sym_tags = new HashMap<>();
         }
     }
     // line number -> tag map
     @SuppressWarnings("java:S116")
-    private final Map<Integer, LineTagMap> line_maps;
+    private final HashMap<Integer, LineTagMap> line_maps;
 
     /**
      * Map from symbol to the line numbers on which the symbol is defined.
      */
-    private final Map<String, Set<Integer>> symbols;
+    private final HashMap<String, Set<Integer>> symbols;
     /**
      * List of all the tags.
      */
-    private final List<Tag> tags;
+    private final ArrayList<Tag> tags;
 
     public Definitions() {
         symbols = new HashMap<>();

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/JFlexTokenizer.java

@@ -18,7 +18,7 @@
  */
 
  /*
- * Copyright (c) 2009, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2025, Oracle and/or its affiliates. All rights reserved.
  * Portions Copyright (c) 2017, 2020, Chris Fraire <cfraire@me.com>.
  */
 package org.opengrok.indexer.analysis;
@@ -49,6 +49,7 @@ public class JFlexTokenizer extends Tokenizer
      * will be owned by the {@link JFlexTokenizer}.
      * @param matcher a defined instance
      */
+    @SuppressWarnings("this-escape")
     public JFlexTokenizer(ScanningSymbolMatcher matcher) {
         if (matcher == null) {
             throw new IllegalArgumentException("`matcher' is null");
@@ -83,12 +84,9 @@ public final void close() throws IOException {
         matcher.yyclose();
     }
 
-    private final CharTermAttribute termAtt = addAttribute(
-        CharTermAttribute.class);
-    private final OffsetAttribute offsetAtt = addAttribute(
-        OffsetAttribute.class);
-    private final PositionIncrementAttribute posIncrAtt = addAttribute(
-        PositionIncrementAttribute.class);
+    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+    private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
+    private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
 
     /**
      * Attempts to advance the stream to the next acceptable token, and updates

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/JFlexXref.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2009, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2025, Oracle and/or its affiliates. All rights reserved.
  * Portions Copyright (c) 2011, Jens Elkner.
  * Portions Copyright (c) 2017, 2020, Chris Fraire <cfraire@me.com>.
  */
@@ -37,8 +37,7 @@
 /**
  * @author Lubos Kosco
  */
-public class JFlexXref implements Xrefer, SymbolMatchedListener,
-        NonSymbolMatchedListener {
+public class JFlexXref implements Xrefer, SymbolMatchedListener, NonSymbolMatchedListener {
 
     /**
      * Used to indicate pre-formatted output with
@@ -99,6 +98,7 @@ public class JFlexXref implements Xrefer, SymbolMatchedListener,
      * will be owned by the {@link JFlexXref}.
      * @param matcher a defined instance
      */
+    @SuppressWarnings("this-escape")
     public JFlexXref(ScanningSymbolMatcher matcher) {
         if (matcher == null) {
             throw new IllegalArgumentException("`matcher' is null");
@@ -109,11 +109,11 @@ public JFlexXref(ScanningSymbolMatcher matcher) {
         // The xrefer will own the matcher, so we won't have to unsubscribe.
 
         userPageLink = RuntimeEnvironment.getInstance().getUserPage();
-        if (userPageLink != null && userPageLink.length() == 0) {
+        if (userPageLink != null && userPageLink.isEmpty()) {
             userPageLink = null;
         }
         userPageSuffix = RuntimeEnvironment.getInstance().getUserPageSuffix();
-        if (userPageSuffix != null && userPageSuffix.length() == 0) {
+        if (userPageSuffix != null && userPageSuffix.isEmpty()) {
             userPageSuffix = null;
         }
     }

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/PathTokenizer.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2025, Oracle and/or its affiliates. All rights reserved.
  * Portions Copyright (c) 2018, Chris Fraire <cfraire@me.com>.
  */
 package org.opengrok.indexer.analysis;
@@ -52,7 +52,9 @@ public class PathTokenizer extends Tokenizer {
     // below should be '/' since we try to convert even windows file separators
     // to unix ones
     public static final char DEFAULT_DELIMITER = '/';
+    @SuppressWarnings("this-escape")
     private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+    @SuppressWarnings("this-escape")
     private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
     private int startPosition = 0;
     private final char delimiter;

opengrok-indexer/src/main/java/org/opengrok/indexer/analysis/plain/DefinitionsTokenStream.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2018, 2020, Chris Fraire <cfraire@me.com>.
  */
 package org.opengrok.indexer.analysis.plain;
@@ -48,12 +48,12 @@ public class DefinitionsTokenStream extends TokenStream {
      */
     private final List<PendingToken> events = new ArrayList<>();
 
-    private final CharTermAttribute termAtt = addAttribute(
-        CharTermAttribute.class);
-    private final OffsetAttribute offsetAtt = addAttribute(
-        OffsetAttribute.class);
-    private final PositionIncrementAttribute posIncrAtt = addAttribute(
-        PositionIncrementAttribute.class);
+    @SuppressWarnings("this-escape")
+    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+    @SuppressWarnings("this-escape")
+    private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
+    @SuppressWarnings("this-escape")
+    private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
 
     private int offset;
 
@@ -65,8 +65,7 @@ public class DefinitionsTokenStream extends TokenStream {
      * @param wrapper an optional instance
      * @throws IOException if I/O error occurs
      */
-    public void initialize(Definitions defs, StreamSource src,
-            ReaderWrapper wrapper) throws IOException {
+    public void initialize(Definitions defs, StreamSource src, ReaderWrapper wrapper) throws IOException {
         if (defs == null) {
             throw new IllegalArgumentException("`defs' is null");
         }