### Question:
NCCChannel extends BaseChannel { protected void sendMessageLength(int len) throws IOException { try { serverOut.write ( ISOUtil.str2bcd ( ISOUtil.zeropad (Integer.toString (len % 10000), 4), true ) ); } catch (ISOException e) { Logger.log (new LogEvent (this, "send-message-length", e)); } } NCCChannel();  NCCChannel(String host, int port, ISOPackager p, byte[] TPDU);  NCCChannel(ISOPackager p, byte[] TPDU);  NCCChannel(ISOPackager p, byte[] TPDU, ServerSocket serverSocket); void setHeader(String header); void setConfiguration(Configuration cfg);  }### Answer:
@Test public void testSendMessageLength() throws Throwable { NCCChannel nCCChannel = new NCCChannel(new BASE24Packager(), "testString".getBytes()); nCCChannel.sendMessageLength(-2147483646); assertTrue(true, "should execute without exception"); }
@Test public void testSendMessageLengthThrowsNullPointerException() throws Throwable { byte[] TPDU = new byte[0]; NCCChannel nCCChannel = new NCCChannel(new ISO87APackager(), TPDU); try { nCCChannel.sendMessageLength(100); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"java.io.DataOutputStream.write(byte[])\" because \"this.serverOut\" is null", ex.getMessage(), "ex.getMessage()"); } } }