Merge branch 'stable-5.8' into stable-5.9

* stable-5.8:
  Add missing @since tags
  Add missing @since tag
  Add missing @since tags
  Remove unused import in ApacheSshTest
  Update maven plugins
  Ignore missing javadoc in test bundles
  storage: file: De-duplicate File.exists()+File.isFile()
  RefDirectory.scanRef: Re-use file existence check done in snapshot creation
  FileSnapshot: Lazy load file store attributes cache
  Update eclipse-jarsigner-plugin to 1.3.2
  Fix p2 repository URLs

Change-Id: I5e7c204c0e4c428df6f3b27ba1fc06326983f27c

26 files changed, 72 insertions, 31 deletions

diff --git a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/GitFilter.java b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/GitFilter.java
index 1769832fba..0957cc80fa 100644
--- a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/GitFilter.java
+++ b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/GitFilter.java
@@ -125,6 +125,7 @@ public class GitFilter extends MetaFilter {
 	 *
 	 * @param h
 	 *            A custom error handler for git-upload-pack.
+	 * @since 5.6
 	 */
 	public void setUploadPackErrorHandler(UploadPackErrorHandler h) {
 		assertNotInitialized();
@@ -163,6 +164,7 @@ public class GitFilter extends MetaFilter {
 	 *
 	 * @param h
 	 *            A custom error handler for git-receive-pack.
+	 * @since 5.7
 	 */
 	public void setReceivePackErrorHandler(ReceivePackErrorHandler h) {
 		assertNotInitialized();
diff --git a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ReceivePackErrorHandler.java b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ReceivePackErrorHandler.java
index ee66cb102f..a7ca4d0931 100644
--- a/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ReceivePackErrorHandler.java
+++ b/org.eclipse.jgit.http.server/src/org/eclipse/jgit/http/server/ReceivePackErrorHandler.java
@@ -31,7 +31,7 @@ import org.eclipse.jgit.transport.ServiceMayNotContinueException;
  * If a custom handler is not specified, JGit will use the default error
  * handler.
  *
- * @since 5.6
+ * @since 5.7
  */
 public interface ReceivePackErrorHandler {
 	/**
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/MockSystemReader.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/MockSystemReader.java
index 664615e456..6bfe70659b 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/MockSystemReader.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/MockSystemReader.java
@@ -80,6 +80,7 @@ public class MockSystemReader extends SystemReader {
 	 * @param userGitConfig
 	 *            set another user-level git config
 	 * @return the old user-level git config
+	 * @since 5.1.9
 	 */
 	public FileBasedConfig setUserGitConfig(FileBasedConfig userGitConfig) {
 		FileBasedConfig old = this.userGitConfig;
@@ -92,6 +93,7 @@ public class MockSystemReader extends SystemReader {
 	 *
 	 * @param jgitConfig
 	 *            set the jgit configuration
+	 * @since 5.5
 	 */
 	public void setJGitConfig(FileBasedConfig jgitConfig) {
 		this.jgitConfig = jgitConfig;
@@ -103,6 +105,7 @@ public class MockSystemReader extends SystemReader {
 	 * @param systemGitConfig
 	 *            the new system-level git config
 	 * @return the old system-level config
+	 * @since 5.1.9
 	 */
 	public FileBasedConfig setSystemGitConfig(FileBasedConfig systemGitConfig) {
 		FileBasedConfig old = this.systemGitConfig;
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepeatRule.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepeatRule.java
index 3db3ba90c2..adcc10cad8 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepeatRule.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepeatRule.java
@@ -60,6 +60,7 @@ public class RepeatRule implements TestRule {
 		 *
 		 * @param message
 		 *            the error message
+		 * @since 5.1.9
 		 */
 		public RepeatedTestException(String message) {
 			super(message);
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepositoryTestCase.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepositoryTestCase.java
index cc84f197aa..2d6490a116 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepositoryTestCase.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/RepositoryTestCase.java
@@ -330,6 +330,7 @@ public abstract class RepositoryTestCase extends LocalDiskRepositoryTestCase {
 	 *         greater than then the lastmodification time of lastfile.
 	 * @throws InterruptedException
 	 * @throws IOException
+	 * @since 5.1.9
 	 */
 	public static Instant fsTick(File lastFile)
 			throws InterruptedException,
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/SeparateClassloaderTestRunner.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/SeparateClassloaderTestRunner.java
index b982787e75..106abf0912 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/SeparateClassloaderTestRunner.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/SeparateClassloaderTestRunner.java
@@ -21,6 +21,8 @@ import org.junit.runners.model.InitializationError;
  * This class is used when it's required to load jgit classes in separate
  * classloader for each test class. It can be needed to isolate static field
  * initialization between separate tests.
+ *
+ * @since 5.5
  */
 public class SeparateClassloaderTestRunner extends BlockJUnit4ClassRunner {
 
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
index a5b3b1f3ac..fc19de0bdf 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
@@ -337,6 +337,7 @@ public class TestRepository<R extends Repository> implements AutoCloseable {
 	 *            zero or more IDs of the commit's parents.
 	 * @return the ID of the new commit.
 	 * @throws Exception
+	 * @since 5.5
 	 */
 	public ObjectId unparsedCommit(ObjectId... parents) throws Exception {
 		return unparsedCommit(1, tree(), parents);
@@ -429,6 +430,7 @@ public class TestRepository<R extends Repository> implements AutoCloseable {
 	 *            zero or more IDs of the commit's parents.
 	 * @return the ID of the new commit.
 	 * @throws Exception
+	 * @since 5.5
 	 */
 	public ObjectId unparsedCommit(final int secDelta, final RevTree tree,
 			final ObjectId... parents) throws Exception {
diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/time/TimeUtil.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/time/TimeUtil.java
index 2ebb8e27db..f93ac57f13 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/time/TimeUtil.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/time/TimeUtil.java
@@ -20,6 +20,8 @@ import org.eclipse.jgit.util.FS;
 
 /**
  * Utility methods for handling timestamps
+ *
+ * @since 5.1.9
  */
 public class TimeUtil {
 	/**
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.target
index 54aeb7a820..c50326c136 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.10" sequenceNumber="1635975443">
+<target name="jgit-4.10" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.tpd b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.tpd
index c0a2db8402..353010a03f 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.tpd
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.10.tpd
@@ -6,3 +6,4 @@ include "orbit/R20200831200620-2020-09.tpd"
 location "https://download.eclipse.org/releases/2018-12/" {
 	org.eclipse.osgi lazy
 }
+
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.11.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.11.target
index 40a40184c6..2e304353cb 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.11.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.11.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.11" sequenceNumber="1635975442">
+<target name="jgit-4.11" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.12.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.12.target
index f6cdc1e668..7374df982f 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.12.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.12.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.12" sequenceNumber="1635975443">
+<target name="jgit-4.12" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.13.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.13.target
index 6f8c2e8e89..76234af7a2 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.13.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.13.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.13" sequenceNumber="1635975443">
+<target name="jgit-4.13" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.target
index 8c91bcd05c..7cb7a75bef 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.14" sequenceNumber="1635975441">
+<target name="jgit-4.14" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.tpd b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.tpd
index eb92809bb4..5b1beaafdf 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.tpd
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.14.tpd
@@ -6,3 +6,4 @@ include "orbit/R20200831200620-2020-09.tpd"
 location "https://download.eclipse.org/releases/2019-12/201912181000/" {
 	org.eclipse.osgi lazy
 }
+
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.15.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.15.target
index 0583cda7b6..4d9ff41850 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.15.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.15.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.15" sequenceNumber="1635975441">
+<target name="jgit-4.15" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.16.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.16.target
index c087e76a88..4577d47f1b 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.16.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.16.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.16" sequenceNumber="1635975357">
+<target name="jgit-4.16" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.17.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.17.target
index aa23a26623..fcbd53d26d 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.17.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.17.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.17-staging" sequenceNumber="1635975515">
+<target name="jgit-4.17-staging" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.6.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.6.target
index 41070856ae..f219cab450 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.6.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.6.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.6" sequenceNumber="1635975454">
+<target name="jgit-4.6" sequenceNumber="1638641816">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.7.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.7.target
index 93a3090d1a..b1feeb4a8d 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.7.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.7.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.7" sequenceNumber="1635975451">
+<target name="jgit-4.7" sequenceNumber="1638641812">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.8.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.8.target
index ff3abcdd09..30c9f126ac 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.8.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.8.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.8" sequenceNumber="1635975443">
+<target name="jgit-4.8" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.9.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.9.target
index c922b9fda2..85fdde5670 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.9.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.9.target
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="jgit-4.9" sequenceNumber="1635975443">
+<target name="jgit-4.9" sequenceNumber="1638641807">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.30.v20200611"/>
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
index 54ff7d29c6..d7f6ef316d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileSnapshot.java
@@ -185,6 +185,12 @@ public class FileSnapshot {
 	private FileStoreAttributes fileStoreAttributeCache;
 
 	/**
+	 * if {@code true} read filesystem time resolution from configuration file
+	 * otherwise use fallback resolution
+	 */
+	private boolean useConfig;
+
+	/**
 	 * Object that uniquely identifies the given file, or {@code
 	 * null} if a file key is not available
 	 */
@@ -220,9 +226,7 @@ public class FileSnapshot {
 	protected FileSnapshot(File file, boolean useConfig) {
 		this.file = file;
 		this.lastRead = Instant.now();
-		this.fileStoreAttributeCache = useConfig
-				? FS.getFileStoreAttributes(file.toPath().getParent())
-				: FALLBACK_FILESTORE_ATTRIBUTES;
+		this.useConfig = useConfig;
 		BasicFileAttributes fileAttributes = null;
 		try {
 			fileAttributes = FS.DETECTED.fileAttributes(file);
@@ -366,7 +370,7 @@ public class FileSnapshot {
 	 *             if sleep was interrupted
 	 */
 	public void waitUntilNotRacy() throws InterruptedException {
-		long timestampResolution = fileStoreAttributeCache
+		long timestampResolution = fileStoreAttributeCache()
 				.getFsTimestampResolution().toNanos();
 		while (isRacyClean(Instant.now())) {
 			TimeUnit.NANOSECONDS.sleep(timestampResolution);
@@ -403,6 +407,15 @@ public class FileSnapshot {
 		return equals(other);
 	}
 
+	/**
+	 * Check if the file exists
+	 *
+	 * @return true if the file exists
+	 */
+	public boolean fileExists() {
+		return !MISSING_FILEKEY.equals(this.fileKey);
+	}
+
 	/** {@inheritDoc} */
 	@Override
 	public int hashCode() {
@@ -487,10 +500,10 @@ public class FileSnapshot {
 	}
 
 	private long getEffectiveRacyThreshold() {
-		long timestampResolution = fileStoreAttributeCache
+		long timestampResolution = fileStoreAttributeCache()
 				.getFsTimestampResolution().toNanos();
-		long minRacyInterval = fileStoreAttributeCache.getMinimalRacyInterval()
-				.toNanos();
+		long minRacyInterval = fileStoreAttributeCache()
+				.getMinimalRacyInterval().toNanos();
 		long max = Math.max(timestampResolution, minRacyInterval);
 		// safety margin: factor 2.5 below 100ms otherwise 1.25
 		return max < 100_000_000L ? max * 5 / 2 : max * 5 / 4;
@@ -550,4 +563,13 @@ public class FileSnapshot {
 		}
 		return changed;
 	}
+
+	private FileStoreAttributes fileStoreAttributeCache() {
+		if (fileStoreAttributeCache == null) {
+			fileStoreAttributeCache = useConfig
+					? FS.getFileStoreAttributes(file.toPath().getParent())
+					: FALLBACK_FILESTORE_ATTRIBUTES;
+		}
+		return fileStoreAttributeCache;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
index e27518690b..7179d140b4 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectoryPackParser.java
@@ -151,7 +151,7 @@ public class ObjectDirectoryPackParser extends PackParser {
 		String p = pack.getAbsolutePath();
 		String i = p.substring(0, p.length() - ".pack".length()) + ".idx"; //$NON-NLS-1$ //$NON-NLS-2$
 		File idx = new File(i);
-		if (idx.exists() && idx.isFile())
+		if (idx.isFile())
 			size += idx.length();
 		return size;
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
index 17a910008c..2167262dd5 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/RefDirectory.java
@@ -1092,10 +1092,14 @@ public class RefDirectory extends RefDatabase {
 		final int limit = 4096;
 		final byte[] buf;
 		FileSnapshot otherSnapshot = FileSnapshot.save(path);
+		if (!otherSnapshot.fileExists()) {
+			return null;
+		}
+
 		try {
 			buf = IO.readSome(path, limit);
 		} catch (FileNotFoundException noFile) {
-			if (path.exists() && path.isFile()) {
+			if (path.isFile()) {
 				throw noFile;
 			}
 			return null; // doesn't exist or no file; not a reference.
diff --git a/pom.xml b/pom.xml
index c2b0339db4..c7d4c649ad 100644
--- a/pom.xml
+++ b/pom.xml
@@ -168,14 +168,14 @@
     <httpcore-version>4.4.12</httpcore-version>
     <slf4j-version>1.7.2</slf4j-version>
     <log4j-version>1.2.15</log4j-version>
-    <maven-javadoc-plugin-version>3.2.0</maven-javadoc-plugin-version>
+    <maven-javadoc-plugin-version>3.3.1</maven-javadoc-plugin-version>
     <tycho-extras-version>1.7.0</tycho-extras-version>
     <gson-version>2.8.2</gson-version>
     <bouncycastle-version>1.65</bouncycastle-version>
-    <spotbugs-maven-plugin-version>4.0.4</spotbugs-maven-plugin-version>
-    <maven-project-info-reports-plugin-version>3.1.0</maven-project-info-reports-plugin-version>
-    <maven-jxr-plugin-version>3.0.0</maven-jxr-plugin-version>
-    <maven-surefire-plugin-version>3.0.0-M4</maven-surefire-plugin-version>
+    <spotbugs-maven-plugin-version>4.3.0</spotbugs-maven-plugin-version>
+    <maven-project-info-reports-plugin-version>3.1.2</maven-project-info-reports-plugin-version>
+    <maven-jxr-plugin-version>3.1.1</maven-jxr-plugin-version>
+    <maven-surefire-plugin-version>3.0.0-M5</maven-surefire-plugin-version>
     <maven-surefire-report-plugin-version>${maven-surefire-plugin-version}</maven-surefire-report-plugin-version>
     <maven-compiler-plugin-version>3.8.1</maven-compiler-plugin-version>
     <plexus-compiler-version>2.8.8</plexus-compiler-version>
@@ -247,7 +247,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-dependency-plugin</artifactId>
-          <version>3.1.2</version>
+          <version>3.2.0</version>
         </plugin>
 
         <plugin>
@@ -299,7 +299,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-pmd-plugin</artifactId>
-          <version>3.13.0</version>
+          <version>3.15.0</version>
           <configuration>
             <sourceEncoding>utf-8</sourceEncoding>
             <minimumTokens>100</minimumTokens>
@@ -337,7 +337,7 @@
         <plugin>
           <groupId>org.jacoco</groupId>
           <artifactId>jacoco-maven-plugin</artifactId>
-          <version>0.8.5</version>
+          <version>0.8.7</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -398,7 +398,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-enforcer-plugin</artifactId>
-        <version>3.0.0-M3</version>
+        <version>3.0.0</version>
         <executions>
           <execution>
             <id>enforce-maven</id>