Java 修饰符（Modifier）声明顺序

from: https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/Modifier.html

public static String toString(int mod)

Return a string describing the access modifier flags in the specified modifier. For example:

    public final synchronized strictfp
 

The modifier names are returned in an order consistent with the suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of  The Java™ Language Specification. The full modifier ordering used by this method is:

public protected private abstract static final transient volatile synchronized native strictfp interface

The  interface modifier discussed in this class is not a true modifier in the Java language and it appears after all other modifiers listed by this method. This method may return a string of modifiers that are not valid modifiers of a Java entity; in other words, no checking is done on the possible validity of the combination of modifiers represented by the input. Note that to perform such checking for a known kind of entity, such as a constructor or method, first AND the argument of  toString with the appropriate mask from a method like  constructorModifiers() or  methodModifiers().

从上面的官方文档中可以知道官方建议的顺序是：

public protected private abstract static final transient volatile synchronized native strictfp interface