More static imports.

bramble-android/src/main/java/org/briarproject/bramble/account/AndroidAccountManager.java

@@ -9,7 +9,6 @@ import org.briarproject.bramble.api.account.AccountManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
 import java.util.logging.Logger;
@@ -18,6 +17,7 @@ import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
 
 class AndroidAccountManager extends AccountManagerImpl
 		implements AccountManager {
@@ -99,7 +99,7 @@ class AndroidAccountManager extends AccountManagerImpl
 			for (File child : children) {
 				String name = child.getName();
 				if (!name.equals("lib") && !name.equals("shared_prefs")) {
-					IoUtils.deleteFileOrDir(child);
+					deleteFileOrDir(child);
 				}
 			}
 		}

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -24,7 +24,6 @@ import java.io.IOException;
 import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.BlockingQueue;
@@ -48,6 +47,7 @@ import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
 import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
 import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
+import static java.util.Collections.shuffle;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
@@ -260,7 +260,7 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			appContext.unregisterReceiver(receiver);
 		}
 		// Shuffle the addresses so we don't always try the same one first
-		Collections.shuffle(addresses);
+		shuffle(addresses);
 		return addresses;
 	}
 

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/AndroidTorPluginFactory.java

 package org.briarproject.bramble.plugin.tor;
 
 import android.content.Context;
-import android.os.Build;
 
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
@@ -26,6 +25,7 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.Immutable;
 import javax.net.SocketFactory;
 
+import static android.os.Build.VERSION.SDK_INT;
 import static java.util.logging.Logger.getLogger;
 
 @Immutable
@@ -104,7 +104,7 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 			return null;
 		}
 		// Use position-independent executable for SDK >= 16
-		if (Build.VERSION.SDK_INT >= 16) architecture += "_pie";
+		if (SDK_INT >= 16) architecture += "_pie";
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);

bramble-android/src/main/java/org/briarproject/bramble/system/AndroidSecureRandomProvider.java

@@ -8,7 +8,6 @@ import android.content.ContentResolver;
 import android.content.Context;
 import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiManager;
-import android.os.Build;
 import android.os.Parcel;
 import android.os.StrictMode;
 import android.provider.Settings;
@@ -23,6 +22,9 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
 import static android.content.Context.WIFI_SERVICE;
+import static android.os.Build.FINGERPRINT;
+import static android.os.Build.SERIAL;
+import static android.os.Build.VERSION.SDK_INT;
 import static android.provider.Settings.Secure.ANDROID_ID;
 
 @Immutable
@@ -45,8 +47,8 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		out.writeInt(android.os.Process.myPid());
 		out.writeInt(android.os.Process.myTid());
 		out.writeInt(android.os.Process.myUid());
-		if (Build.FINGERPRINT != null) out.writeUTF(Build.FINGERPRINT);
-		if (Build.SERIAL != null) out.writeUTF(Build.SERIAL);
+		if (FINGERPRINT != null) out.writeUTF(FINGERPRINT);
+		if (SERIAL != null) out.writeUTF(SERIAL);
 		ContentResolver contentResolver = appContext.getContentResolver();
 		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
 		if (id != null) out.writeUTF(id);
@@ -74,15 +76,13 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		// Silence strict mode
 		StrictMode.ThreadPolicy tp = StrictMode.allowThreadDiskWrites();
 		super.writeSeed();
-		if (Build.VERSION.SDK_INT >= 16 && Build.VERSION.SDK_INT <= 18)
-			applyOpenSslFix();
+		if (SDK_INT >= 16 && SDK_INT <= 18) applyOpenSslFix();
 		StrictMode.setThreadPolicy(tp);
 	}
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
 	private void applyOpenSslFix() {
-		byte[] seed = new UnixSecureRandomSpi().engineGenerateSeed(
-				SEED_LENGTH);
+		byte[] seed = new UnixSecureRandomSpi().engineGenerateSeed(SEED_LENGTH);
 		try {
 			// Seed the OpenSSL PRNG
 			Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -3,17 +3,19 @@ package org.briarproject.bramble.util;
 import android.annotation.SuppressLint;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
-import android.os.Build;
 import android.provider.Settings;
 
 import java.io.File;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
 import static android.content.Context.MODE_PRIVATE;
+import static android.os.Build.CPU_ABI;
+import static android.os.Build.CPU_ABI2;
+import static android.os.Build.SUPPORTED_ABIS;
 import static android.os.Build.VERSION.SDK_INT;
+import static java.util.Arrays.asList;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 public class AndroidUtils {
@@ -27,10 +29,10 @@ public class AndroidUtils {
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
 		if (SDK_INT >= 21) {
-			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
+			abis.addAll(asList(SUPPORTED_ABIS));
 		} else {
-			abis.add(Build.CPU_ABI);
-			if (Build.CPU_ABI2 != null) abis.add(Build.CPU_ABI2);
+			abis.add(CPU_ABI);
+			if (CPU_ABI2 != null) abis.add(CPU_ABI2);
 		}
 		return abis;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/Multiset.java

@@ -2,7 +2,6 @@ package org.briarproject.bramble.api;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.NoSuchElementException;
@@ -10,6 +9,8 @@ import java.util.Set;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Collections.unmodifiableSet;
+
 @NotThreadSafe
 @NotNullByDefault
 public class Multiset<T> {
@@ -96,6 +97,6 @@ public class Multiset<T> {
 	 * is unmodifiable.
 	 */
 	public Set<T> keySet() {
-		return Collections.unmodifiableSet(map.keySet());
+		return unmodifiableSet(map.keySet());
 	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/client/BdfMessageContext.java

@@ -5,10 +5,11 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
 
 import java.util.Collection;
-import java.util.Collections;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.Collections.emptyList;
+
 @Immutable
 @NotNullByDefault
 public class BdfMessageContext {
@@ -23,7 +24,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.emptyList());
+		this(dictionary, emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfList.java

@@ -4,12 +4,12 @@ import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Arrays.asList;
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 
 @NotThreadSafe
@@ -22,7 +22,7 @@ public class BdfList extends ArrayList<Object> {
 	 * </pre>
 	 */
 	public static BdfList of(Object... items) {
-		return new BdfList(Arrays.asList(items));
+		return new BdfList(asList(items));
 	}
 
 	public BdfList() {

bramble-api/src/main/java/org/briarproject/bramble/api/db/Transaction.java

@@ -3,11 +3,12 @@ package org.briarproject.bramble.api.db;
 import org.briarproject.bramble.api.event.Event;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.util.Collections.emptyList;
+
 /**
  * A wrapper around a database transaction. Transactions are not thread-safe.
  */
@@ -53,7 +54,7 @@ public class Transaction {
 	 * Returns any events attached to the transaction.
 	 */
 	public List<Event> getEvents() {
-		if (events == null) return Collections.emptyList();
+		if (events == null) return emptyList();
 		return events;
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageContext.java

@@ -4,10 +4,11 @@ import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.util.Collection;
-import java.util.Collections;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.Collections.emptyList;
+
 @Immutable
 @NotNullByDefault
 public class MessageContext {
@@ -22,7 +23,7 @@ public class MessageContext {
 	}
 
 	public MessageContext(Metadata metadata) {
-		this(metadata, Collections.emptyList());
+		this(metadata, emptyList());
 	}
 
 	public Metadata getMetadata() {

bramble-api/src/test/java/org/briarproject/bramble/api/data/BdfDictionaryTest.java

@@ -8,6 +8,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.Map.Entry;
 
+import static java.util.Collections.singletonMap;
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
@@ -19,15 +20,15 @@ public class BdfDictionaryTest extends BrambleTestCase {
 	public void testConstructors() {
 		assertEquals(Collections.<String, Object>emptyMap(),
 				new BdfDictionary());
-		assertEquals(Collections.singletonMap("foo", NULL_VALUE),
-				new BdfDictionary(Collections.singletonMap("foo", NULL_VALUE)));
+		assertEquals(singletonMap("foo", NULL_VALUE),
+				new BdfDictionary(singletonMap("foo", NULL_VALUE)));
 	}
 
 	@Test
 	public void testFactoryMethod() {
 		assertEquals(Collections.<String, Object>emptyMap(),
 				BdfDictionary.of());
-		assertEquals(Collections.singletonMap("foo", NULL_VALUE),
+		assertEquals(singletonMap("foo", NULL_VALUE),
 				BdfDictionary.of(new BdfEntry("foo", NULL_VALUE)));
 	}
 

bramble-api/src/test/java/org/briarproject/bramble/api/data/BdfListTest.java

@@ -5,9 +5,8 @@ import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.junit.Test;
 
-import java.util.Arrays;
-import java.util.Collections;
-
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
@@ -16,15 +15,15 @@ public class BdfListTest extends BrambleTestCase {
 
 	@Test
 	public void testConstructors() {
-		assertEquals(Collections.emptyList(), new BdfList());
-		assertEquals(Arrays.asList(1, 2, NULL_VALUE),
-				new BdfList(Arrays.asList(1, 2, NULL_VALUE)));
+		assertEquals(emptyList(), new BdfList());
+		assertEquals(asList(1, 2, NULL_VALUE),
+				new BdfList(asList(1, 2, NULL_VALUE)));
 	}
 
 	@Test
 	public void testFactoryMethod() {
-		assertEquals(Collections.emptyList(), BdfList.of());
-		assertEquals(Arrays.asList(1, 2, NULL_VALUE),
+		assertEquals(emptyList(), BdfList.of());
+		assertEquals(asList(1, 2, NULL_VALUE),
 				BdfList.of(1, 2, NULL_VALUE));
 	}
 

bramble-api/src/test/java/org/briarproject/bramble/test/TestUtils.java

@@ -12,12 +12,10 @@ import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -25,6 +23,7 @@ import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static java.util.Arrays.asList;
+import static java.util.Collections.sort;
 import static org.briarproject.bramble.api.identity.Author.FORMAT_VERSION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
@@ -33,6 +32,7 @@ import static org.briarproject.bramble.api.properties.TransportPropertyConstants
 import static org.briarproject.bramble.api.sync.ClientId.MAX_CLIENT_ID_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
 import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 
 public class TestUtils {
@@ -48,7 +48,7 @@ public class TestUtils {
 	}
 
 	public static void deleteTestDirectory(File testDir) {
-		IoUtils.deleteFileOrDir(testDir);
+		deleteFileOrDir(testDir);
 		testDir.getParentFile().delete(); // Delete if empty
 	}
 
@@ -145,7 +145,7 @@ public class TestUtils {
 		if (size == 0) throw new IllegalArgumentException();
 		List<Double> sorted = new ArrayList<>(size);
 		for (Number n : samples) sorted.add(n.doubleValue());
-		Collections.sort(sorted);
+		sort(sorted);
 		if (size % 2 == 1) return sorted.get(size / 2);
 		double low = sorted.get(size / 2 - 1), high = sorted.get(size / 2);
 		return (low + high) / 2;

bramble-core/src/main/java/org/briarproject/bramble/account/AccountManagerImpl.java

@@ -8,7 +8,6 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.util.IoUtils;
 
 import java.io.BufferedReader;
 import java.io.File;
@@ -23,6 +22,7 @@ import javax.inject.Inject;
 
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.deleteFileOrDir;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.fromHexString;
 import static org.briarproject.bramble.util.StringUtils.toHexString;
@@ -182,8 +182,8 @@ class AccountManagerImpl implements AccountManager {
 	public void deleteAccount() {
 		synchronized (stateChangeLock) {
 			LOG.info("Deleting account");
-			IoUtils.deleteFileOrDir(databaseConfig.getDatabaseKeyDirectory());
-			IoUtils.deleteFileOrDir(databaseConfig.getDatabaseDirectory());
+			deleteFileOrDir(databaseConfig.getDatabaseKeyDirectory());
+			deleteFileOrDir(databaseConfig.getDatabaseDirectory());
 			databaseKey = null;
 		}
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoComponentImpl.java

@@ -28,6 +28,7 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static java.lang.System.arraycopy;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.ByteUtils.INT_32_BYTES;
@@ -190,7 +191,7 @@ class CryptoComponentImpl implements CryptoComponent {
 		PrivateKey ourPriv = ourKeyPair.getPrivate();
 		byte[][] hashInputs = new byte[inputs.length + 1][];
 		hashInputs[0] = performRawKeyAgreement(ourPriv, theirPublicKey);
-		System.arraycopy(inputs, 0, hashInputs, 1, inputs.length);
+		arraycopy(inputs, 0, hashInputs, 1, inputs.length);
 		byte[] hash = hash(label, hashInputs);
 		if (hash.length != SecretKey.LENGTH) throw new IllegalStateException();
 		return new SecretKey(hash);
@@ -299,13 +300,13 @@ class CryptoComponentImpl implements CryptoComponent {
 		output[outputOff] = PBKDF_FORMAT_SCRYPT;
 		outputOff++;
 		// Salt
-		System.arraycopy(salt, 0, output, outputOff, salt.length);
+		arraycopy(salt, 0, output, outputOff, salt.length);
 		outputOff += salt.length;
 		// Cost parameter
 		writeUint32(cost, output, outputOff);
 		outputOff += INT_32_BYTES;
 		// IV
-		System.arraycopy(iv, 0, output, outputOff, iv.length);
+		arraycopy(iv, 0, output, outputOff, iv.length);
 		outputOff += iv.length;
 		// Initialise the cipher and encrypt the plaintext
 		try {
@@ -335,7 +336,7 @@ class CryptoComponentImpl implements CryptoComponent {
 			return null; // Unknown format
 		// Salt
 		byte[] salt = new byte[PBKDF_SALT_BYTES];
-		System.arraycopy(input, inputOff, salt, 0, salt.length);
+		arraycopy(input, inputOff, salt, 0, salt.length);
 		inputOff += salt.length;
 		// Cost parameter
 		long cost = readUint32(input, inputOff);
@@ -344,7 +345,7 @@ class CryptoComponentImpl implements CryptoComponent {
 			return null; // Invalid cost parameter
 		// IV
 		byte[] iv = new byte[STORAGE_IV_BYTES];
-		System.arraycopy(input, inputOff, iv, 0, iv.length);
+		arraycopy(input, inputOff, iv, 0, iv.length);
 		inputOff += iv.length;
 		// Derive the key from the password
 		SecretKey key = passwordBasedKdf.deriveKey(password, salt, (int) cost);

bramble-core/src/main/java/org/briarproject/bramble/crypto/Curve25519KeyParser.java

@@ -7,6 +7,8 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.security.GeneralSecurityException;
 
+import static java.lang.System.arraycopy;
+
 @NotNullByDefault
 class Curve25519KeyParser implements KeyParser {
 
@@ -26,7 +28,7 @@ class Curve25519KeyParser implements KeyParser {
 
 	static byte[] clamp(byte[] b) {
 		byte[] clamped = new byte[32];
-		System.arraycopy(b, 0, clamped, 0, 32);
+		arraycopy(b, 0, clamped, 0, 32);
 		clamped[0] &= 248;
 		clamped[31] &= 127;
 		clamped[31] |= 64;

bramble-core/src/main/java/org/briarproject/bramble/crypto/KeyAgreementCryptoImpl.java

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.crypto.SecretKey;
 
 import javax.inject.Inject;
 
+import static java.lang.System.arraycopy;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
 
 class KeyAgreementCryptoImpl implements KeyAgreementCrypto {
@@ -24,7 +25,7 @@ class KeyAgreementCryptoImpl implements KeyAgreementCrypto {
 		byte[] hash = crypto.hash(COMMIT_LABEL, publicKey.getEncoded());
 		// The output is the first COMMIT_LENGTH bytes of the hash
 		byte[] commitment = new byte[COMMIT_LENGTH];
-		System.arraycopy(hash, 0, commitment, 0, COMMIT_LENGTH);
+		arraycopy(hash, 0, commitment, 0, COMMIT_LENGTH);
 		return commitment;
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/crypto/Sec1KeyParser.java

@@ -16,6 +16,7 @@ import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
 
+import static java.lang.System.arraycopy;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -56,12 +57,12 @@ class Sec1KeyParser implements KeyParser {
 		if (encodedKey[0] != 4) throw new GeneralSecurityException();
 		// The x co-ordinate must be >= 0 and < p
 		byte[] xBytes = new byte[bytesPerInt];
-		System.arraycopy(encodedKey, 1, xBytes, 0, bytesPerInt);
+		arraycopy(encodedKey, 1, xBytes, 0, bytesPerInt);
 		BigInteger x = new BigInteger(1, xBytes); // Positive signum
 		if (x.compareTo(modulus) >= 0) throw new GeneralSecurityException();
 		// The y co-ordinate must be >= 0 and < p
 		byte[] yBytes = new byte[bytesPerInt];
-		System.arraycopy(encodedKey, 1 + bytesPerInt, yBytes, 0, bytesPerInt);
+		arraycopy(encodedKey, 1 + bytesPerInt, yBytes, 0, bytesPerInt);
 		BigInteger y = new BigInteger(1, yBytes); // Positive signum
 		if (y.compareTo(modulus) >= 0) throw new GeneralSecurityException();
 		// Verify that y^2 == x^3 + ax + b (mod p)

bramble-core/src/main/java/org/briarproject/bramble/crypto/Sec1Utils.java

@@ -2,6 +2,8 @@ package org.briarproject.bramble.crypto;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import static java.lang.System.arraycopy;
+
 @NotNullByDefault
 class Sec1Utils {
 
@@ -10,10 +12,10 @@ class Sec1Utils {
 		if (src.length < destLen) {
 			int padding = destLen - src.length;
 			for (int i = destOff; i < destOff + padding; i++) dest[i] = 0;
-			System.arraycopy(src, 0, dest, destOff + padding, src.length);
+			arraycopy(src, 0, dest, destOff + padding, src.length);
 		} else {
 			int srcOff = src.length - destLen;
-			System.arraycopy(src, srcOff, dest, destOff, destLen);
+			arraycopy(src, srcOff, dest, destOff, destLen);
 		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/crypto/StreamDecrypterImpl.java

@@ -13,6 +13,7 @@ import java.security.GeneralSecurityException;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.lang.System.arraycopy;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_HEADER_PLAINTEXT_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_NONCE_LENGTH;
@@ -131,7 +132,7 @@ class StreamDecrypterImpl implements StreamDecrypter {
 		}
 		// Extract the nonce
 		byte[] streamHeaderNonce = new byte[STREAM_HEADER_NONCE_LENGTH];
-		System.arraycopy(streamHeaderCiphertext, 0, streamHeaderNonce, 0,
+		arraycopy(streamHeaderCiphertext, 0, streamHeaderNonce, 0,
 				STREAM_HEADER_NONCE_LENGTH);
 		// Decrypt and authenticate the stream header
 		try {
@@ -155,7 +156,7 @@ class StreamDecrypterImpl implements StreamDecrypter {
 		if (receivedStreamNumber != streamNumber) throw new FormatException();
 		// Extract the frame key
 		byte[] frameKeyBytes = new byte[SecretKey.LENGTH];
-		System.arraycopy(streamHeaderPlaintext, INT_16_BYTES + INT_64_BYTES,
+		arraycopy(streamHeaderPlaintext, INT_16_BYTES + INT_64_BYTES,
 				frameKeyBytes, 0, SecretKey.LENGTH);
 		frameKey = new SecretKey(frameKeyBytes);
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/StreamEncrypterImpl.java

@@ -11,6 +11,7 @@ import java.security.GeneralSecurityException;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
+import static java.lang.System.arraycopy;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_HEADER_PLAINTEXT_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.FRAME_NONCE_LENGTH;
@@ -89,7 +90,7 @@ class StreamEncrypterImpl implements StreamEncrypter {
 			throw new RuntimeException(badCipher);
 		}
 		// Combine the payload and padding
-		System.arraycopy(payload, 0, framePlaintext, 0, payloadLength);
+		arraycopy(payload, 0, framePlaintext, 0, payloadLength);
 		for (int i = 0; i < paddingLength; i++)
 			framePlaintext[payloadLength + i] = 0;
 		// Encrypt and authenticate the payload and padding
@@ -121,10 +122,10 @@ class StreamEncrypterImpl implements StreamEncrypter {
 		byte[] streamHeaderPlaintext = new byte[STREAM_HEADER_PLAINTEXT_LENGTH];
 		writeUint16(PROTOCOL_VERSION, streamHeaderPlaintext, 0);
 		writeUint64(streamNumber, streamHeaderPlaintext, INT_16_BYTES);
-		System.arraycopy(frameKey.getBytes(), 0, streamHeaderPlaintext,
+		arraycopy(frameKey.getBytes(), 0, streamHeaderPlaintext,
 				INT_16_BYTES + INT_64_BYTES, SecretKey.LENGTH);
 		byte[] streamHeaderCiphertext = new byte[STREAM_HEADER_LENGTH];
-		System.arraycopy(streamHeaderNonce, 0, streamHeaderCiphertext, 0,
+		arraycopy(streamHeaderNonce, 0, streamHeaderCiphertext, 0,
 				STREAM_HEADER_NONCE_LENGTH);
 		// Encrypt and authenticate the stream header key
 		try {

bramble-core/src/main/java/org/briarproject/bramble/crypto/TransportCryptoImpl.java

@@ -12,6 +12,7 @@ import org.spongycastle.crypto.digests.Blake2bDigest;
 
 import javax.inject.Inject;
 
+import static java.lang.System.arraycopy;
 import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_HEADER_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.ALICE_TAG_LABEL;
 import static org.briarproject.bramble.api.transport.TransportConstants.BOB_HEADER_LABEL;