개인학적조회시 아래처럼 오류가 납니다. 확인 부탁드립니다.

500 Servlet Exception
java.lang.StringIndexOutOfBoundsException: String index out of range: 4
 at java.lang.Throwable.fillInStackTrace(Native Method)
 at java.lang.Throwable.fillInStackTrace(Compiled Code)
 at java.lang.Throwable.<init>(Compiled Code)
 at java.lang.Exception.<init>(Compiled Code)
 at java.lang.RuntimeException.<init>(Compiled Code)
 at java.lang.IndexOutOfBoundsException.<init>(Compiled Code)
 at java.lang.StringIndexOutOfBoundsException.<init>(Compiled Code)
 at java.lang.String.substring(Compiled Code)
 at clientlib.ac_client030.GetHakJek(Compiled Code)
 at clientlib.ac_client030.doPost(Compiled Code)
 at javax.servlet.http.HttpServlet.service(Compiled Code)
 at javax.servlet.http.HttpServlet.service(Compiled Code)
 at com.caucho.server.http.FilterChainServlet.doFilter(Compiled Code)
 at com.caucho.server.http.Invocation.service(Compiled Code)
 at com.caucho.server.http.CacheInvocation.service(Compiled Code)
 at com.caucho.server.http.RunnerRequest.handleRequest(Compiled Code)
 at com.caucho.server.http.RunnerRequest.handleConnection(Compiled Code)
 at com.caucho.server.TcpConnection.run(Compiled Code)
 at java.lang.Thread.run(Compiled Code)