log916 B
Java Stack Trace (log)
A realistic Java stack trace — a Spring-style NullPointerException with a nested 'Caused by' chain and '... N more' elision. A fixture for testing stack-trace parsers, error groupers, and log viewers.
Preview — first 12 lineslog
2026-01-15 10:22:41.882 ERROR 14872 --- [http-nio-8080-exec-3] c.e.api.OrderController : Unhandled exception
java.lang.NullPointerException: Cannot invoke "com.example.model.Customer.getEmail()" because "customer" is null
at com.example.api.OrderService.notify(OrderService.java:142)
at com.example.api.OrderService.placeOrder(OrderService.java:88)
at com.example.api.OrderController.create(OrderController.java:54)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:255)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089)
Caused by: java.lang.IllegalStateException: customer lookup returned no rows for id=4021
at com.example.api.CustomerRepository.findById(CustomerRepository.java:67)
... 6 more
Specifications
- Language
- Java
- Exception
- NullPointerException
- Has Caused By
- true
- Frames
- 8
What is a .log file?
LOG files are plain-text records of events emitted by software, typically one entry per line with a timestamp, severity, and message. There is no single standard, so formats range from unstructured text to structured JSON lines. They are central to debugging, monitoring, and auditing.
How to use this file
Use an example LOG file to test log parsers, timestamp and severity extraction, line-oriented streaming, and ingestion into monitoring or analysis pipelines.
Related files
- logApache Access Log — Combined Format (log)An Apache access log in the Combined Log Format — the Common fields plus referer and user-agent. A realistic web-server log for testing access-log parsers, analytics, and grok patterns.
- logApache Access Log — Common Format (log)An Apache access log in the Common Log Format (CLF) — client, timestamp, request line, status, and byte count. Deterministic, with reserved documentation IPs. Paired with a Combined-format twin for testing log parsers.
- logDocker Container Log — json-file driver (log)A Docker json-file container log — one JSON object per line with the log text, stream (stdout/stderr), and an RFC 3339 timestamp, exactly as Docker's default logging driver writes it. A fixture for container-log shippers and parsers.
- jsonlJSON-Lines Application LogA structured application log with one JSON object per line at info/debug/warn/error levels — for testing log ingestion.
- logKubernetes Component Log — klog (log)A Kubernetes-component log in the klog/glog format — a severity letter, timestamp, thread id, and source location prefix followed by the message. A fixture for testing klog parsers and severity extraction.
- logNginx Access LogAn nginx combined-format access log with several requests, including a 403 and a 404 — for testing log parsers.
Generated by generation/data_logs.py. Free for any use, no attribution required — license.