feat: Retry twice to grab the lock on startup

src/main/java/io/confluent/connect/hdfs/wal/QFSWAL.java

@@ -31,6 +31,7 @@
 import java.util.Timer;
 import java.util.TimerTask;
 import java.util.UUID;
+import java.util.function.Supplier;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -129,8 +130,18 @@ private Lock createOrRenameLock() {
       this.storage.create(this.lockDir);
     }
 
-    if (!findAliveLocks().isEmpty()) {
-      throw new ConnectException("Lock has been acquired by another process");
+    // It gives two chance of grabbing the lock on startup.
+    // This should help when the new task comes up sooner than the expiry of the previous lock.
+    if (!findAliveLocks().isEmpty()){
+      try {
+        Thread.sleep(this.lockTimeout.toMillis());
+      } catch (InterruptedException e) {
+        throw new RuntimeException(e);
+      }
+
+      if (!findAliveLocks().isEmpty()) {
+        throw new ConnectException("Lock has been acquired by another process");
+      }
     }
 
     Lock newLock = getNewLock();