diff --git a/src/org/omegat/util/TmxEscapingWriterFactory.java b/src/org/omegat/util/TmxEscapingWriterFactory.java
index 19d152c413..985e9ecd28 100644
--- a/src/org/omegat/util/TmxEscapingWriterFactory.java
+++ b/src/org/omegat/util/TmxEscapingWriterFactory.java
@@ -28,7 +28,6 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
-import java.io.UnsupportedEncodingException;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
@@ -39,27 +38,25 @@
 public class TmxEscapingWriterFactory implements EscapingWriterFactory {
 
     @Override
-    public Writer createEscapingWriterFor(final Writer writer, final String s)
-            throws UnsupportedEncodingException {
+    public Writer createEscapingWriterFor(@NotNull final Writer writer, final String s) {
         return new EscapeWriter(writer);
     }
 
     @Override
-    public Writer createEscapingWriterFor(final OutputStream outputStream, final String s)
-            throws UnsupportedEncodingException {
+    public Writer createEscapingWriterFor(@NotNull final OutputStream outputStream, final String s) {
         return new EscapeWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
     }
 
     public static class EscapeWriter extends Writer {
 
         // Copy from woodstox:com.ctc.wstx.sw.BufferingXmlWriter
-        private static final int[] QUOTABLE_TEXT_CHARS;
+        private static final byte[] QUOTABLE_TEXT_CHARS;
         private static final int HIGH_ENC = 0xFFFE;
 
         static {
-            int[] q = new int[4096];
-            Arrays.fill(q, 0, 32, 1);
-            Arrays.fill(q, 127, 160, 1);
+            byte[] q = new byte[256];
+            Arrays.fill(q, 0, 32, (byte) 1);
+            Arrays.fill(q, 127, 160, (byte) 1);
             q['\t'] = 0;
             q['\n'] = 0;
             q['<'] = 1;
@@ -86,6 +83,7 @@ public EscapeWriter(@NotNull Writer delegate) {
          * @param len
          *            Number of characters to write
          * @throws IOException
+         *             when underlying writer object raises.
          */
         @Override
         public void write(@NotNull final char[] cbuf, final int off, final int len) throws IOException {
@@ -96,7 +94,7 @@ public void write(@NotNull final char[] cbuf, final int off, final int len) thro
                 String ent = null;
                 for (; offset < end; offset++) {
                     int c = cbuf[offset];
-                    if (c < 4096 && QUOTABLE_TEXT_CHARS[c] != 0) {
+                    if (c < 256 && QUOTABLE_TEXT_CHARS[c] != 0) {
                         if (c == '<') {
                             ent = "&lt;";
                             break;