Eclipse Build Refreshing Hang

This behavior just started two days ago. When I save a file, automatic build kicks in. (I don't want to turn off automatic builds.) Eclipse blocks the UI during a build. It says "Refreshing".

I took call stacks of Eclipse when hung and when okay. I found this thread. What can I do to fix the hang?

Here's what I tried:

Manually refreshing the project hangs
Checked Error view and found nothing
Checked .metadata/.log and found nothing
Delete .metadata/.plugins/org.eclipse.core.resources/.project
Run Eclipse with -clean option
Run Eclipse with -clean and -clearPersistedState options
Increase heap size

I noticed that saving a file does not trigger the UI blocking hang, but the build does take a while. Making a change and saving the file again while the build is going causes the UI to block.

"Worker-49: Building" #498 prio=5 os_prio=0 cpu=9125.00ms elapsed=662.08s tid=0x0000017e2de80070 nid=0x6c80 runnable  [0x0000003ca1cfd000]
   java.lang.Thread.State: RUNNABLE
    at org.eclipse.core.internal.filesystem.local.LocalFileNatives.internalGetFileInfoW(Native Method)
    at org.eclipse.core.internal.filesystem.local.LocalFileNatives.fetchFileInfo(LocalFileNatives.java:116)
    at org.eclipse.core.internal.filesystem.local.LocalFileHandler.fetchFileInfo(LocalFileHandler.java:30)
    at org.eclipse.core.internal.filesystem.local.LocalFileNativesManager.fetchFileInfo(LocalFileNativesManager.java:65)
    at org.eclipse.core.internal.filesystem.local.LocalFile.fetchInfo(LocalFile.java:161)
    at org.eclipse.core.filesystem.provider.FileStore.fetchInfo(FileStore.java:260)
    at org.eclipse.core.filesystem.provider.FileStore.childInfos(FileStore.java:99)
    at org.eclipse.core.internal.localstore.UnifiedTree.getLocalList(UnifiedTree.java:360)
    at org.eclipse.core.internal.localstore.UnifiedTree.addChildren(UnifiedTree.java:148)
    at org.eclipse.core.internal.localstore.UnifiedTree.addNodeChildrenToQueue(UnifiedTree.java:254)
    at org.eclipse.core.internal.localstore.UnifiedTree.accept(UnifiedTree.java:120)
    at org.eclipse.core.internal.localstore.FileSystemResourceManager.refreshResource(FileSystemResourceManager.java:978)
    at org.eclipse.core.internal.localstore.FileSystemResourceManager.refresh(FileSystemResourceManager.java:961)
    at org.eclipse.core.internal.resources.Resource.refreshLocal(Resource.java:1573)
    at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.refreshResources(MavenBuilderImpl.java:280)
    at org.eclipse.m2e.core.internal.builder.MavenBuilderImpl.build(MavenBuilderImpl.java:176)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:164)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$1.method(MavenBuilder.java:1)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.lambda$1(MavenBuilder.java:109)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$$Lambda$1256/0x0000000801a3aa90.call(Unknown Source)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:394)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:228)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.lambda$0(MavenBuilder.java:100)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod$$Lambda$1254/0x0000000801a3a388.call(Unknown Source)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.executeBare(MavenExecutionContext.java:394)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:275)
    at org.eclipse.m2e.core.internal.embedder.MavenExecutionContext.execute(MavenExecutionContext.java:214)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder$BuildMethod.execute(MavenBuilder.java:83)
    at org.eclipse.m2e.core.internal.builder.MavenBuilder.build(MavenBuilder.java:192)
    at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1020)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:247)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:303)
    at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:392)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
    at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:395)
    at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:506)
    at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:454)
    at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:536)
    at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:196)
    at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:289)
    at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

@howlger suggested that I open the Maven Workspace Build view in Eclipse. Here is what it shows.

Configuration

Eclipse: 2023-03 (4.27.0 - build 20230309-1520)
Windows: 11 version 22H2 build 22621.1555

Solution

Eclipse will do a refresh operation as part of a build. If the project directory has a deep large tree of directories, then this will take a while. Reducing the size of the tree of directories resolves this.