Configuring the classpath for a Gradle project in Visual Studio Code (VSCode) involves specifying the dependencies and build settings.
Here's a guide for both IDEs:

Search java source

Searching source configs inside .classpath and *.prefs files

• Search java source config by substring path="src/main/java"
• Replace output attribute to gradle build folder output="build/classes/java/main"

result looks like:

<classpathentry excluding="**/*.txt" output="build/classes/java/main" kind="src" path="src/main/java">
  <attributes>
    <attribute name="gradle_scope" value="main"/>
    <attribute name="gradle_used_by_scope" value="main,test"/>
  </attributes>
</classpathentry>
<classpathentry output="build/classes/java/test" kind="src" path="src/test/java">
  <attributes>
    <attribute name="gradle_scope" value="test"/>
    <attribute name="gradle_used_by_scope" value="test"/>
    <attribute name="test" value="true"/>
  </attributes>
</classpathentry>

• Search annotation config bin/generated-sources/annotations and bin/generated-test-sources/annotations
• Replace with build/generated/sources/annotationProcessor/java/main and build/generated/sources/annotationProcessor/java/test

• Verify all output directory are configured by searching subtring bin/ for .classpath and *.prefs files

My full working .classpath configuration

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
  <classpathentry excluding="**/*.txt" kind="src" output="build/classes/java/main" path="src/main/java">
    <attributes>
      <attribute name="gradle_scope" value="main"/>
      <attribute name="gradle_used_by_scope" value="main,test"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/classes/groovy/main" path="src/main/groovy">
    <attributes>
      <attribute name="gradle_scope" value="main"/>
      <attribute name="gradle_used_by_scope" value="main,test"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/resources/main" path="src/main/resources">
    <attributes>
      <attribute name="gradle_scope" value="main"/>
      <attribute name="gradle_used_by_scope" value="main,test"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/classes/java/test" path="src/test/java">
    <attributes>
      <attribute name="gradle_scope" value="test"/>
      <attribute name="gradle_used_by_scope" value="test"/>
      <attribute name="test" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/classes/kotlin/test" path="src/test/kotlin">
    <attributes>
      <attribute name="gradle_scope" value="test"/>
      <attribute name="gradle_used_by_scope" value="test"/>
      <attribute name="test" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/resources/test" path="src/test/resources">
    <attributes>
      <attribute name="gradle_scope" value="test"/>
      <attribute name="gradle_used_by_scope" value="test"/>
      <attribute name="test" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-19/"/>
  <classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
  <classpathentry kind="src" output="build/test" path="build/generated-test-sources/annotations">
    <attributes>
      <attribute name="optional" value="true"/>
      <attribute name="test" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" path="build/generated-sources/annotations">
    <attributes>
      <attribute name="optional" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" path="bin/generated-sources/annotations">
    <attributes>
      <attribute name="optional" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="src" output="build/test" path="bin/generated-test-sources/annotations">
    <attributes>
      <attribute name="optional" value="true"/>
      <attribute name="test" value="true"/>
    </attributes>
  </classpathentry>
  <classpathentry kind="output" path="build/default"/>
</classpath>

Configure .vscode/settings.json

• In the .vscode directory (created by the above task), there should be a settings.json file.
• Ensure it has the necessary classpath settings.

Example settings.json:

{
  "java.project.outputPath": "build",
  "java.import.generatesMetadataFilesAtProjectRoot": false,
  "java.editor.reloadChangedSources": "auto",
  "java.configuration.updateBuildConfiguration": "disabled",
  "java.server.launchMode": "Hybrid",
  "java.project.referencedLibraries": [
    "build/classes/java/main",
    "build/resources/main",
    "lib/**/*.jar"
  ],
  "java.edit.smartSemicolonDetection.enabled": true,
  "terminal.integrated.env.windows": {
    "PATH": "${workspaceFolder};${workspaceFolder}\\bin;${workspaceFolder}\\node_modules\\.bin;${env:PATH}"
  },
  "terminal.integrated.env.linux": {
    "PATH": "${workspaceFolder}:${workspaceFolder}/bin:${workspaceFolder}/node_modules/.bin:${env:PATH}"
  },
  "java.sharedIndexes.enabled": "off",
  "java.project.resourceFilters": [
    "node_modules",
    "\\.git",
    "\\.cache"
  ]
}

Conclusion

Now you don't have to wait long when opening a Java project in VScode with the Redhat Java plugin, because all build output is synchronized from Gradle and Eclipse JDT which are used by the Redhat Java extension.

And this trick can change the output folder from Redhat Java Extension to the Gradle build folder.

You can checkout our repository of gradle+eclipse in vscode - sample project