Audit of a Java Application (TomCat+MySQL) - repost

We have Java JSP application that is running on Linux Server web server accessible through SSH only. This application has numerous CRONS that regularly connect on Google Databases through APIs and compare data in order to write them into a relational MySQL Database. This application manages a high volume of data and sometimes it happens that the logs of the application show some Java Errors that really slows the application down for hours. For instance, during several hours in a row, the application shows "[login to view URL] : GC overhead limit exceeded" or other errors that make the application unable to implement the cron tasks timely and properly. We need a Java expert, who will be able to audit the application IN PRODUCTION by analyzing the logs and proposing some turnarounds. GC overheat limit error means that the garbage collection is using more than 98% of the application. So we need a proposal that will not only ignore the exception, but make it not happen. Thanks for your proposals.