Studio Assembly OutOfMemoryError on Large Files
The error java.lang.OutOfMemoryError: Java heap space at com.workday.esb.assembly.AssemblyRunner
What it means
The assembly tried to hold too much data in memory at once — typically by loading a large file or report result wholesale instead of streaming it. Workday Studio assemblies run with a fixed heap; one big DOM parse or aggregation of a large dataset can exhaust it.
Troubleshooting
- Check the size of the input that triggered the failure (file size or record count) versus runs that succeeded.
- Look for steps that materialize the whole message: DOM-based XSLT on the full document, aggregator steps collecting everything before output, or variables holding the full payload.
- Confirm whether the integration uses streaming-capable components (splitter with streaming, SAX-style processing) or loads everything up front.
⚡ Quick fix
Re-run with the input split into smaller batches (or filter the source report) to get today's run through.
✓ Permanent fix
Restructure the assembly to stream: split the input early, process chunk-by-chunk, avoid full-document XSLT on large payloads, and write incremental output instead of aggregating in memory. Add an input-size check that fails fast with a clear message when a file exceeds the designed limit.