 <p>Under normal circumstances. Java properties of the variable names are lowercase letter, such as: userName, ShowMessage, but there are special circumstances, taking into account certain interesting English acronym (USA, XML, etc.), JavaBean also allows capital letters beginning the attributes variable name, but must meet the first two letters of the variable is either all uppercase or all lowercase "requirements, such as: the IDCODE ICcard IDCODE property variable name is legal, but the iC, iCcard, iDCode attribute variables The name is illegal.</p>