fix 5.x too many open files (#1970)

* close inputStream safety

* FIX NPE in AlarmService

* fix 5.x too many open files bug

* checkstyle bug

* checkstyle bug

* checkstyle bug

apm-collector/apm-collector-analysis/analysis-segment-parser/segment-parser-provider/src/main/java/org/apache/skywalking/apm/collector/analysis/segment/parser/provider/buffer/OffsetManager.java

@@ -21,7 +21,6 @@ package org.apache.skywalking.apm.collector.analysis.segment.parser.provider.buf
 import java.io.File;
 import java.io.FilenameFilter;
 import java.io.IOException;
-import java.io.RandomAccessFile;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import org.apache.skywalking.apm.collector.core.util.CollectionUtils;
@@ -44,7 +43,6 @@ public enum OffsetManager {
     private File offsetFile;
     private Offset offset;
     private boolean initialized = false;
-    private RandomAccessFile randomAccessFile = null;
     private String lastOffsetRecord = Const.EMPTY_STRING;
 
     public synchronized void initialize() throws IOException {
@@ -95,7 +93,7 @@ public enum OffsetManager {
             if (offsetFile.length() >= BufferFileConfig.BUFFER_OFFSET_MAX_FILE_SIZE) {
                 nextFile();
             }
-            FileUtils.INSTANCE.writeAppendToLast(offsetFile, randomAccessFile, offsetRecord);
+            FileUtils.INSTANCE.writeAppendToLast(offsetFile, offsetRecord);
             lastOffsetRecord = offsetRecord;
         }
     }

apm-collector/apm-collector-analysis/analysis-segment-parser/segment-parser-provider/src/main/java/org/apache/skywalking/apm/collector/analysis/segment/parser/provider/buffer/SegmentBufferManager.java

@@ -55,6 +55,9 @@ public enum SegmentBufferManager {
                 if (StringUtils.isNotEmpty(writeFileName)) {
                     File dataFile = new File(BufferFileConfig.BUFFER_PATH + writeFileName);
                     if (dataFile.exists()) {
+                        if (outputStream != null) {
+                            outputStream.close();
+                        }
                         outputStream = new FileOutputStream(new File(BufferFileConfig.BUFFER_PATH + writeFileName), true);
                     } else {
                         newDataFile();

apm-collector/apm-collector-core/src/main/java/org/apache/skywalking/apm/collector/core/util/FileUtils.java

@@ -19,7 +19,6 @@
 package org.apache.skywalking.apm.collector.core.util;
 
 import java.io.File;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import org.slf4j.Logger;
@@ -68,21 +67,24 @@ public enum FileUtils {
         return Const.EMPTY_STRING;
     }
 
-    public void writeAppendToLast(File file, RandomAccessFile randomAccessFile, String value) {
-        if (randomAccessFile == null) {
-            try {
-                randomAccessFile = new RandomAccessFile(file, "rwd");
-            } catch (FileNotFoundException e) {
-                logger.error(e.getMessage(), e);
-            }
-        }
+    public void writeAppendToLast(File file, String value) {
+        RandomAccessFile randomAccessFile = null;
         try {
+            randomAccessFile = new RandomAccessFile(file, "rwd");
             long length = randomAccessFile.length();
             randomAccessFile.seek(length);
             randomAccessFile.writeBytes(System.lineSeparator());
             randomAccessFile.writeBytes(value);
         } catch (IOException e) {
             logger.error(e.getMessage(), e);
+        } finally {
+            if (randomAccessFile != null) {
+                try {
+                    randomAccessFile.close();
+                } catch (IOException e) {
+                    logger.error(e.getMessage(), e);
+                }
+            }
         }
     }
 }