import java.lang.reflect.*; ... boolean isNumeric(Class aClass, String aStr) { Metod lMeth= aClass.getMethod("valueOf", new Class[] {String.class}); try { lMeth.invoke(null, new Object[] {aStr}); } catch(Exception eEx) { return false; } } boolean isNumeric(String aStr) { return isNumeric(Byte.class, aStr) || isNumeric(Short.class, aStr) || isNumeric(Integer.class, aStr) || isNumeric(Long.class, aStr) || isNumeric(Float.class, aStr) || isNumeric(Double.class, aStr); }