Merge branch 'stable-5.10' into stable-5.11

* stable-5.10:
  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: I84c73e11381c31566a12033db94e9afdcef5b705

28 files changed, 75 insertions, 34 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 64556acc1c..32af08c179 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
@@ -338,6 +338,7 @@ 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 4a4dc92c43..c8c56b21b8 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 0232156a49..54e4a09ee5 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
@@ -339,6 +339,7 @@ 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);
@@ -431,6 +432,7 @@ 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 757d0c5abc..d37f5cce41 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="1635977193">
+<target name="jgit-4.10" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 ed443a6fbf..216ff5631e 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/R20210223232630-2021-03.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 2dba940c50..0323bc7dda 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="1635977193">
+<target name="jgit-4.11" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 56d0f1f945..d0e3d4b6a0 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="1635977193">
+<target name="jgit-4.12" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 ee6a0f60ff..ef27e80ccb 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="1635977193">
+<target name="jgit-4.13" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 6e2a4350cf..e4c4e0d9a8 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="1635977193">
+<target name="jgit-4.14" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 e0a730e678..6b1e0f44fc 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/R20210223232630-2021-03.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 5f40f85877..d799873027 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="1635977193">
+<target name="jgit-4.15" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 b588f51b9d..5ff1efc91b 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="1635977193">
+<target name="jgit-4.16" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 e218a08ea3..1c3af70133 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" sequenceNumber="1635977193">
+<target name="jgit-4.17" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.18.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.18.target
index 5485a342d3..2944eb43c5 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.18.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.18.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-4.18" sequenceNumber="1635977193">
+<target name="jgit-4.18" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
diff --git a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.19.target b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.19.target
index 94adf11257..bce01691b5 100644
--- a/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.19.target
+++ b/org.eclipse.jgit.packaging/org.eclipse.jgit.target/jgit-4.19.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-4.19" sequenceNumber="1635977193">
+<target name="jgit-4.19" sequenceNumber="1638646047">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 523f9b1786..278c3d2542 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="1635977193">
+<target name="jgit-4.6" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 33d6adcd36..461e1fee9a 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="1635977193">
+<target name="jgit-4.7" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 8c05a423d9..c88f4721a7 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="1635977193">
+<target name="jgit-4.8" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 eff2628248..3670fa80a9 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="1635977193">
+<target name="jgit-4.9" sequenceNumber="1638646045">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jetty.client" version="9.4.36.v20210114"/>
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 8c48cd94b0..5ab973f533 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
@@ -187,6 +187,12 @@ 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
 	 */
@@ -222,9 +228,7 @@ public class FileSnapshot {
 	protected FileSnapshot(File file, boolean useConfig) {
 		this.file = file;
 		this.lastRead = Instant.now();
-		this.fileStoreAttributeCache = useConfig
-				? FS.getFileStoreAttributes(file.toPath())
-				: FALLBACK_FILESTORE_ATTRIBUTES;
+		this.useConfig = useConfig;
 		BasicFileAttributes fileAttributes = null;
 		try {
 			fileAttributes = FS.DETECTED.fileAttributes(file);
@@ -379,7 +383,7 @@ 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);
@@ -416,6 +420,15 @@ 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() {
@@ -500,10 +513,10 @@ 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;
@@ -563,4 +576,13 @@ 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 dba8ccd99b..1d05f33395 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
@@ -152,7 +152,7 @@ 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 4afd974a19..f668c17d14 100644
--- a/pom.xml
+++ b/pom.xml
@@ -168,13 +168,13 @@
     <httpcore-version>4.4.14</httpcore-version>
     <slf4j-version>1.7.30</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>2.8.6</gson-version>
     <bouncycastle-version>1.65</bouncycastle-version>
-    <spotbugs-maven-plugin-version>4.2.0</spotbugs-maven-plugin-version>
-    <maven-project-info-reports-plugin-version>3.1.1</maven-project-info-reports-plugin-version>
-    <maven-jxr-plugin-version>3.0.0</maven-jxr-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>
@@ -255,7 +255,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-dependency-plugin</artifactId>
-          <version>3.1.2</version>
+          <version>3.2.0</version>
         </plugin>
 
         <plugin>
@@ -307,7 +307,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-pmd-plugin</artifactId>
-          <version>3.14.0</version>
+          <version>3.15.0</version>
           <configuration>
             <sourceEncoding>utf-8</sourceEncoding>
             <minimumTokens>100</minimumTokens>
@@ -345,7 +345,7 @@
         <plugin>
           <groupId>org.jacoco</groupId>
           <artifactId>jacoco-maven-plugin</artifactId>
-          <version>0.8.6</version>
+          <version>0.8.7</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -411,7 +411,7 @@
       <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>
@@ -860,12 +860,12 @@
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-compiler-plugin</artifactId>
-            <configuration>
+                <configuration>
               <fork>true</fork>
               <compilerArgs combine.children="append">
                 <arg>-J-Xbootclasspath/p:${settings.localRepository}/com/google/errorprone/javac/${javac.version}/javac-${javac.version}.jar</arg>
               </compilerArgs>
-            </configuration>
+                </configuration>
           </plugin>
         </plugins>
       </build>