JSPs compile to Java code at run time. This is helpful if we want to test code changes without a build and deploy. However, if errors are introduced, they may not be spotted till it’s too late. A useful compromise is to validate JSPs at build time to verify that they will compile. The validator catches syntax errors before the application deploys and starts. This speeds up our build and test cycle and prevents silly mistakes slipping through to production code.
Stuart 'Stevie' Leitch on Software Development, Java Technologies, Security and Testing