### Question:
BitUtil { public static String long2Bin(long source) { return Long.toBinaryString(source); }  static String int2Bin(int source); static int bin2Int(String source); static String long2Bin(long source); static long bin2Long(String source); static boolean getIntBit(int source, int pos); static int setIntBit(int source, int pos, boolean value); static boolean getLongBit(long source, int pos); static long setLongBit(long source, int pos, boolean value);  }### Answer:
@Test public void long2Bin() { assertEquals("1_0000_0000_0000_0000_0000_0000_0000_0000".replace("_", ""), BitUtil.long2Bin(4294967296L)); }