请问老师 这个错误是什么原因？

警告: Failed to initialize a channel. Closing: [id: 0x78476f2e, /0:0:0:0:0:0:0:1:51525 => /0:0:0:0:0:0:0:1:8888] java.lang.IllegalArgumentException: Duplicate handler name: aggregator


提示这行代码有问题：
e.pipeline().addLast("aggregator", new HttpObjectAggregator(65536));