http status500

HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error that prevented it from fulfilling this request.exception java.lang.NullPointerException
javabean.JavaBean.setGender(JavaBean.java:58)
sql.SQLHeadInformation.methodhead(SQLHeadInformation.java:48)
servlet.Information.doPost(Information.java:69)
servlet.Information.doGet(Information.java:46)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
com.EncondingFilter.doFilter(EncondingFilter.java:33)这个怎么解决？求解，困扰我许久了