Agent just stopped working.

[willipl1972]

Running Red Hat 9.6, Cassandra 4.1.9, Openjdk 11. The agent was working fine and it just stopped working with the following in the logs:

WARN [prometheus-netty-pool-0] 2025-07-18 11:46:20,295 DefaultChannelPipeline.java:1152 - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.nio.BufferOverflowException: null
at java.base/java.nio.HeapByteBuffer.put(HeapByteBuffer.java:249)
at com.zegelin.prometheus.exposition.NioExpositionSink.writeBytes(NioExpositionSink.java:27)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.writeLabels(TextFormatMetricFamilyWriter.java:111)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.writeLabelSets(TextFormatMetricFamilyWriter.java:123)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.writeMetric(TextFormatMetricFamilyWriter.java:141)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.lambda$null$3(TextFormatMetricFamilyWriter.java:185)
at com.google.common.collect.ImmutableList.forEach(ImmutableList.java:407)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.lambda$visit$4(TextFormatMetricFamilyWriter.java:184)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter$MetricVisitor.lambda$metricWriter$0(TextFormatMetricFamilyWriter.java:155)
at com.zegelin.prometheus.exposition.text.TextFormatMetricFamilyWriter.writeMetric(TextFormatMetricFamilyWriter.java:227)
at com.zegelin.prometheus.exposition.text.TextFormatExposition.nextSlice(TextFormatExposition.java:81)
at com.zegelin.prometheus.exposition.FormattedByteChannel.read(FormattedByteChannel.java:24)
at io.netty.handler.stream.ChunkedNioStream.readChunk(ChunkedNioStream.java:112)
at io.netty.handler.stream.ChunkedNioStream.readChunk(ChunkedNioStream.java:31)
at io.netty.handler.codec.http.HttpChunkedInput.readChunk(HttpChunkedInput.java:102)
at io.netty.handler.codec.http.HttpChunkedInput.readChunk(HttpChunkedInput.java:43)
at io.netty.handler.stream.ChunkedWriteHandler.doFlush(ChunkedWriteHandler.java:230)
at io.netty.handler.stream.ChunkedWriteHandler.flush(ChunkedWriteHandler.java:132)
at io.netty.channel.AbstractChannelHandlerContext.invokeFlush0(AbstractChannelHandlerContext.java:750)
at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:765)
at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:808)
at com.zegelin.cassandra.exporter.netty.HttpHandler.sendMetrics(HttpHandler.java:303)
at com.zegelin.cassandra.exporter.netty.HttpHandler.channelRead0(HttpHandler.java:94)
at com.zegelin.cassandra.exporter.netty.HttpHandler.channelRead0(HttpHandler.java:39)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296)
at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.base/java.lang.Thread.run(Thread.java:829)

Receive the following with curl:

curl http://localhost:9500/metrics
curl: (18) transfer closed with outstanding read data remaining

[redsfyre]

Same exception on rhel 8.10, openjdk 11, cassandra 4.1.10 - All fresh install
Compiled the project by changing the cassandra version on pom.xml but no luck :(