move to JDK17 (graphhopper#2827)

* move to JDK17

* Update pom.xml

Co-authored-by: otbutz <[email protected]>

* simplify cleanMappedByteBuffer

---------

Co-authored-by: otbutz <[email protected]>

Author: karussell

.github/workflows/publish-maven-central.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-java@v3
         with:
-          java-version: 8
+          java-version: 17
           distribution: temurin
           server-id: ossrh
           server-username: MAVEN_USERNAME

README.md

@@ -85,7 +85,7 @@ To get started you can try [GraphHopper Maps](README.md#graphhopper-maps), read
 
 ## Installation
 
-To install the [GraphHopper Maps](https://graphhopper.com/maps/) UI and the web service locally you [need a JVM](https://adoptium.net) (>= Java 8) and do:
+To install the [GraphHopper Maps](https://graphhopper.com/maps/) UI and the web service locally you [need a JVM](https://adoptium.net) (>= Java 17) and do:
 
 ```bash
 wget https://repo1.maven.org/maven2/com/graphhopper/graphhopper-web/8.0/graphhopper-web-8.0.jar https://raw.githubusercontent.com/graphhopper/graphhopper/8.x/config-example.yml http://download.geofabrik.de/europe/germany/berlin-latest.osm.pbf

core/src/main/java/com/graphhopper/storage/MMapDataAccess.java

@@ -17,7 +17,6 @@
  */
 package com.graphhopper.storage;
 
-import com.graphhopper.util.Constants;
 import com.graphhopper.util.Helper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -56,8 +55,6 @@
  */
 public final class MMapDataAccess extends AbstractDataAccess {
 
-    private static final Logger LOGGER = LoggerFactory.getLogger(MMapDataAccess.class);
-
     private final boolean allowWrites;
     private RandomAccessFile raFile;
     private final List<MappedByteBuffer> segments = new ArrayList<>();
@@ -67,96 +64,35 @@ public final class MMapDataAccess extends AbstractDataAccess {
         this.allowWrites = allowWrites;
     }
 
-    public static boolean jreIsMinimumJava9() {
-        final StringTokenizer st = new StringTokenizer(System.getProperty("java.specification.version"), ".");
-        int JVM_MAJOR_VERSION = Integer.parseInt(st.nextToken());
-        int JVM_MINOR_VERSION;
-        if (st.hasMoreTokens()) {
-            JVM_MINOR_VERSION = Integer.parseInt(st.nextToken());
-        } else {
-            JVM_MINOR_VERSION = 0;
-        }
-        return JVM_MAJOR_VERSION > 1 || (JVM_MAJOR_VERSION == 1 && JVM_MINOR_VERSION >= 9);
-    }
-
     public static void cleanMappedByteBuffer(final ByteBuffer buffer) {
         // TODO avoid reflection on every call
         try {
             AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() {
                 @Override
                 public Object run() throws Exception {
-                    if (jreIsMinimumJava9()) {
-                        // >=JDK9 class sun.misc.Unsafe { void invokeCleaner(ByteBuffer buf) }
-                        final Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
-                        // fetch the unsafe instance and bind it to the virtual MethodHandle
-                        final Field f = unsafeClass.getDeclaredField("theUnsafe");
-                        f.setAccessible(true);
-                        final Object theUnsafe = f.get(null);
-                        final Method method = unsafeClass.getDeclaredMethod("invokeCleaner", ByteBuffer.class);
-                        try {
-                            method.invoke(theUnsafe, buffer);
-                            return null;
-                        } catch (Throwable t) {
-                            throw new RuntimeException(t);
-                        }
-                    }
-
-                    if (buffer.getClass().getSimpleName().equals("MappedByteBufferAdapter")) {
-                        if (!Constants.ANDROID)
-                            throw new RuntimeException("MappedByteBufferAdapter only supported for Android at the moment");
-
-                        // For Android 4.1 call ((MappedByteBufferAdapter)buffer).free() see #914
-                        Class<?> directByteBufferClass = Class.forName("java.nio.MappedByteBufferAdapter");
-                        callBufferFree(buffer, directByteBufferClass);
-                    } else {
-                        // <=JDK8 class DirectByteBuffer { sun.misc.Cleaner cleaner(Buffer buf) }
-                        //        then call sun.misc.Cleaner.clean
-                        final Class<?> directByteBufferClass = Class.forName("java.nio.DirectByteBuffer");
-                        try {
-                            final Method dbbCleanerMethod = directByteBufferClass.getMethod("cleaner");
-                            dbbCleanerMethod.setAccessible(true);
-                            // call: cleaner = ((DirectByteBuffer)buffer).cleaner()
-                            final Object cleaner = dbbCleanerMethod.invoke(buffer);
-                            if (cleaner != null) {
-                                final Class<?> cleanerMethodReturnType = dbbCleanerMethod.getReturnType();
-                                final Method cleanMethod = cleanerMethodReturnType.getDeclaredMethod("clean");
-                                cleanMethod.setAccessible(true);
-                                // call: ((sun.misc.Cleaner)cleaner).clean()
-                                cleanMethod.invoke(cleaner);
-                            }
-                        } catch (NoSuchMethodException ex2) {
-                            if (Constants.ANDROID)
-                                // For Android 5.1.1 call ((DirectByteBuffer)buffer).free() see #933
-                                callBufferFree(buffer, directByteBufferClass);
-                            else
-                                // ignore if method cleaner or clean is not available
-                                LOGGER.warn("NoSuchMethodException | " + System.getProperty("java.version"), ex2);
-                        }
+                    // >=JDK9 class sun.misc.Unsafe { void invokeCleaner(ByteBuffer buf) }
+                    final Class<?> unsafeClass = Class.forName("sun.misc.Unsafe");
+                    // fetch the unsafe instance and bind it to the virtual MethodHandle
+                    final Field f = unsafeClass.getDeclaredField("theUnsafe");
+                    f.setAccessible(true);
+                    final Object theUnsafe = f.get(null);
+                    final Method method = unsafeClass.getDeclaredMethod("invokeCleaner", ByteBuffer.class);
+                    try {
+                        method.invoke(theUnsafe, buffer);
+                        return null;
+                    } catch (Throwable t) {
+                        throw new RuntimeException(t);
                     }
-
-                    return null;
                 }
             });
         } catch (PrivilegedActionException e) {
             throw new RuntimeException("Unable to unmap the mapped buffer", e);
         }
     }
 
-    private static void callBufferFree(ByteBuffer buffer, Class<?> directByteBufferClass)
-            throws InvocationTargetException, IllegalAccessException {
-        try {
-            final Method dbbFreeMethod = directByteBufferClass.getMethod("free");
-            dbbFreeMethod.setAccessible(true);
-            dbbFreeMethod.invoke(buffer);
-        } catch (NoSuchMethodException ex2) {
-            LOGGER.warn("NoSuchMethodException | " + System.getProperty("java.version"), ex2);
-        }
-    }
-
     private void initRandomAccessFile() {
-        if (raFile != null) {
+        if (raFile != null)
             return;
-        }
 
         try {
             // raFile necessary for loadExisting and create

core/src/main/java/com/graphhopper/util/Constants.java

@@ -42,18 +42,10 @@ public class Constants {
      * True iff running on Linux.
      */
     public static final boolean LINUX = OS_NAME.startsWith("Linux");
-    /**
-     * True iff running on Android.
-     */
-    public static final boolean ANDROID = System.getProperty("java.vendor").contains("Android");
     /**
      * True iff running on Windows.
      */
     public static final boolean WINDOWS = OS_NAME.startsWith("Windows");
-    /**
-     * True iff running on SunOS.
-     */
-    public static final boolean SUN_OS = OS_NAME.startsWith("SunOS");
     /**
      * True iff running on Mac OS X
      */

core/src/main/java/com/graphhopper/util/GitInfo.java

@@ -56,6 +56,6 @@ public boolean isDirty() {
     }
 
     public String toString() {
-        return Helper.join("|", Arrays.asList(commitHash, branch, "dirty=" + dirty, commitTime, commitMessage));
+        return String.join("|", Arrays.asList(commitHash, branch, "dirty=" + dirty, commitTime, commitMessage));
     }
 }

core/src/test/java/com/graphhopper/routing/EdgeBasedRoutingAlgorithmTest.java

@@ -196,7 +196,7 @@ public void testRandomGraph(String algoStr) {
         }
         if (strictViolations.size() > 0.05 * numQueries) {
             fail("Too many strict violations: " + strictViolations.size() + "/" + numQueries + "\n" +
-                    Helper.join("\n", strictViolations));
+                    String.join("\n", strictViolations));
         }
     }
 

core/src/test/java/com/graphhopper/routing/RandomCHRoutingTest.java

@@ -169,7 +169,7 @@ private void runRandomTest(Fixture f, Random rnd) {
             }
             if (strictViolations.size() > 0.05 * numQueries) {
                 fail("Too many strict violations: " + strictViolations.size() + "/" + numQueries + "\n" +
-                        Helper.join("\n", strictViolations));
+                        String.join("\n", strictViolations));
             }
         }
     }

pom.xml

@@ -16,7 +16,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 
-        <maven.compiler.target>1.8</maven.compiler.target>
+        <maven.compiler.target>17</maven.compiler.target>
 
         <!-- We always had this disabled as it is disabled by default in debian JDK builds, but when we
              switched to another JDK on travis it was enabled implicitly. Our javadocs are not ready for this
@@ -183,8 +183,7 @@
                         <compilerArgument>-Xlint:deprecation</compilerArgument>
                         -->
                         <fork>true</fork>
-                        <source>1.8</source>
-                        <target>1.8</target>
+                        <release>17</release>
                     </configuration>
                 </plugin>
 

web-api/src/main/java/com/graphhopper/util/Helper.java

@@ -413,20 +413,6 @@ public static String underScoreToCamelCase(String key) {
         return sb.toString();
     }
 
-    /**
-     * Equivalent to java 8 String#join
-     */
-    public static String join(String delimiter, List<String> strings) {
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < strings.size(); i++) {
-            if (i > 0) {
-                sb.append(delimiter);
-            }
-            sb.append(strings.get(i));
-        }
-        return sb.toString();
-    }
-
     /**
      * parses a string like [a,b,c]
      */