Log Viewer 
Log Viewer allows you to view all log and trace messages that are generated in the whole SAP NetWeaver system landscape. These log records assist you to monitor and diagnose problems.
To access the Log Viewer tool, choose 
SAP NetWeaver Administrator 
Problem Management Logs and Traces Log Viewer 
.
You can alternatively use the quick link: http://<host>:<port>/nwa/logs.
Integration
In SAP NetWeaver Administrator you can configure the Log Viewer. For this purpose, choose Log Configuration tool from Related Links.
More information: Log Configuration with SAP NetWeaver Administrator
Features
Log Viewer allows you to:
View general, development and specific logs in a set of predefined views. More information: Predefined Views
Know the certain system problem via the trace messages
Control the amount of log data displayed
Merge list formatted logs and traces
View ABAP log messages
View logs and traces from an inactive AS Java. More information:Using Standalone Log Viewer
Filter logs and traces. More information:Filtering Logs and Traces
Download log content. More information: Downloading Logs and Traces
Create, export and import custom views. More information: Creating, Exporting and Importing Custom Views