code: public static ECKey fromNodeId(byte[] nodeId) {
          check(nodeId.length == 64, "Expected a 64 byte node id");
          byte[] pubBytes = new byte[65];
          System.arraycopy(nodeId, 0, pubBytes, 1, nodeId.length);
          pubBytes[0] = 0x04; // uncompressed
          return ECKey.fromPublicOnly(pubBytes);
      }
docs: Recover the public key from an encoded node id.
  
  @param nodeId
  a 64-byte X,Y point pair
  @return ECKey