Faster and cleaner way to obtain UTF-8 encoded form.

Instead of specifying character encoding by name, the faster, cleaner,
and safer way is to use StandardCharsets.UTF_8.

Bug: 27461702
Change-Id: I897284d3ceeb44a21cc74de09a9b25f6aec8c205

tools/apksigner/core/src/com/android/apksigner/core/internal/jar/ManifestParser.java

@@ -16,7 +16,7 @@
 
 package com.android.apksigner.core.internal.jar;
 
-import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -220,11 +220,7 @@ public class ManifestParser {
         if (lineLengthBytes == 0) {
             return "";
         }
-        try {
+        return new String(mManifest, startOffset, lineLengthBytes, StandardCharsets.UTF_8);
-            return new String(mManifest, startOffset, lineLengthBytes, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException("UTF-8 character encoding not supported", e);
-        }
     }
 
 

tools/apksigner/core/src/com/android/apksigner/core/internal/jar/ManifestWriter.java

@@ -18,6 +18,7 @@ package com.android.apksigner.core.internal.jar;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.Set;
 import java.util.SortedMap;
@@ -81,7 +82,7 @@ public abstract class ManifestWriter {
     }
 
     private static void writeLine(OutputStream  out, String line) throws IOException {
-        byte[] lineBytes = line.getBytes("UTF-8");
+        byte[] lineBytes = line.getBytes(StandardCharsets.UTF_8);
         int offset = 0;
         int remaining = lineBytes.length;
         boolean firstLine = true;

tools/apksigner/core/src/com/android/apksigner/core/internal/zip/CentralDirectoryRecord.java

@@ -18,9 +18,9 @@ package com.android.apksigner.core.internal.zip;
 
 import com.android.apksigner.core.zip.ZipFormatException;
 
-import java.io.UnsupportedEncodingException;
 import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.util.Comparator;
 
 /**
@@ -168,11 +168,7 @@ public class CentralDirectoryRecord {
                 record.position(originalPosition);
             }
         }
-        try {
+        return new String(nameBytes, nameBytesOffset, nameLengthBytes, StandardCharsets.UTF_8);
-            return new String(nameBytes, nameBytesOffset, nameLengthBytes, "UTF-8");
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException("UTF-8 character encoding not supported", e);
-        }
     }
 
     private static class ByLocalFileHeaderOffsetComparator

tools/apksigner/core/src/com/android/apksigner/core/internal/zip/LocalFileHeader.java

@@ -20,6 +20,7 @@ import java.io.Closeable;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
 import java.util.zip.DataFormatException;
 import java.util.zip.Inflater;
 
@@ -93,7 +94,7 @@ public class LocalFileHeader {
         // exhibited when reading an APK for the purposes of verifying its signatures.
 
         String entryName = cdRecord.getName();
-        byte[] cdNameBytes = entryName.getBytes("UTF-8");
+        byte[] cdNameBytes = entryName.getBytes(StandardCharsets.UTF_8);
         int headerSizeWithName = HEADER_SIZE_BYTES + cdNameBytes.length;
         long localFileHeaderOffsetInArchive = cdRecord.getLocalFileHeaderOffset();
         long headerEndInArchive = localFileHeaderOffsetInArchive + headerSizeWithName;

tools/signapk/src/com/android/signapk/SignApk.java

@@ -57,6 +57,7 @@ import java.io.OutputStream;
 import java.lang.reflect.Constructor;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
 import java.security.GeneralSecurityException;
 import java.security.Key;
 import java.security.KeyFactory;
@@ -717,7 +718,7 @@ class SignApk {
         // archive comment, so that tools that display the comment
         // (hopefully) show something sensible.
         // TODO: anything more useful we can put in this message?
-        byte[] message = "signed by SignApk".getBytes("UTF-8");
+        byte[] message = "signed by SignApk".getBytes(StandardCharsets.UTF_8);
         temp.write(message);
         temp.write(0);