Minor suggestions and replaced use of obsolete Date-API (#76)

Author: Peldan

ecs-logging-core/src/main/java/co/elastic/logging/EcsJsonSerializer.java

@@ -27,12 +27,14 @@
 import java.io.PrintWriter;
 import java.io.Writer;
 import java.util.Map;
+import java.util.regex.Pattern;
 
 public class EcsJsonSerializer {
 
     private static final TimestampSerializer TIMESTAMP_SERIALIZER = new TimestampSerializer();
     private static final ThreadLocal<StringBuilder> messageStringBuilder = new ThreadLocal<StringBuilder>();
     private static final  String NEW_LINE = System.getProperty("line.separator");
+    private static final Pattern NEW_LINE_PATTERN = Pattern.compile("\\n");
 
     public static CharSequence toNullSafeString(final CharSequence s) {
         return s == null ? "" : s;
@@ -196,7 +198,7 @@ public static void serializeException(StringBuilder builder, String exceptionCla
         builder.append("\",");
         if (stackTraceAsArray) {
             builder.append("\"error.stack_trace\":[").append(NEW_LINE);
-            for (String line : stackTrace.split("\\n")) {
+            for (String line : NEW_LINE_PATTERN.split(stackTrace)) {
                 appendQuoted(builder, line);
             }
             builder.append("]");

jul-ecs-formatter/src/test/java/co/elastic/logging/jul/JulLoggingTestTest.java

@@ -50,7 +50,7 @@
 
 public class JulLoggingTestTest extends AbstractEcsLoggingTest {
 
-    private final class InMemoryStreamHandler extends StreamHandler {
+    private static final class InMemoryStreamHandler extends StreamHandler {
         private InMemoryStreamHandler(OutputStream out, Formatter formatter) {
             super(out, formatter);
         }
@@ -74,9 +74,9 @@ public void publish(LogRecord record) {
 
     private final EcsFormatter formatter = new EcsFormatter();
 
-    private Logger logger = Logger.getLogger("");
+    private final Logger logger = Logger.getLogger("");
 
-    private  ByteArrayOutputStream out = new ByteArrayOutputStream();
+    private final ByteArrayOutputStream out = new ByteArrayOutputStream();
 
     private LogRecord record;
 

log4j-ecs-layout/src/test/java/co/elastic/logging/log4j/ListAppender.java

@@ -31,7 +31,7 @@
 import java.util.List;
 
 class ListAppender extends AppenderSkeleton {
-    private List<String> logEvents = new ArrayList<>();
+    private final List<String> logEvents = new ArrayList<String>();
 
     @Override
     protected void append(LoggingEvent event) {

log4j2-ecs-layout/src/main/java/co/elastic/logging/log4j2/EcsLayout.java

@@ -59,7 +59,7 @@
 public class EcsLayout extends AbstractStringLayout {
 
     public static final Charset UTF_8 = Charset.forName("UTF-8");
-    public static final String[] JSON_FORMAT = {"JSON"};
+    static final String[] JSON_FORMAT = {"JSON"};
 
     private final TriConsumer<String, Object, StringBuilder> WRITE_MDC = new TriConsumer<String, Object, StringBuilder>() {
         @Override
@@ -336,7 +336,7 @@ public static class Builder extends AbstractStringLayout.Builder<EcsLayout.Build
         }
 
         public KeyValuePair[] getAdditionalFields() {
-            return additionalFields;
+            return additionalFields.clone();
         }
 
         public String getServiceName() {
@@ -361,7 +361,7 @@ public boolean isIncludeOrigin() {
          * @return this builder
          */
         public EcsLayout.Builder setAdditionalFields(final KeyValuePair[] additionalFields) {
-            this.additionalFields = additionalFields;
+            this.additionalFields = additionalFields.clone();
             return asBuilder();
         }
 

log4j2-ecs-layout/src/test/java/co/elastic/logging/log4j2/ParameterizedStructuredMessage.java

@@ -39,6 +39,7 @@ public void accept(String key, Object value, StringBuilder builder) {
             }
         }
     };
+    private static final long serialVersionUID = -170788861790476303L;
 
     private final String message;
 

logback-ecs-encoder/src/main/java/co/elastic/logging/logback/EcsEncoder.java

@@ -47,7 +47,7 @@ public class EcsEncoder extends EncoderBase<ILoggingEvent> {
     private boolean includeMarkers = false;
     private ThrowableProxyConverter throwableProxyConverter;
     private boolean includeOrigin;
-    private List<Pair> additionalFields = new ArrayList<Pair>();
+    private final List<Pair> additionalFields = new ArrayList<Pair>();
 
     @Override
     public byte[] headerBytes() {