how does spring implement this technology?

manpreet Best Answer 2 years ago

today,i learned that we could use spring's @AutoWired annotation to complete auto-injection, @AutoWired could be used in many conditions ,like

@AutoWired
public void setInstrument(Instrument instrument){
  this.instrument = instrument;
}

but we can also put the @AutoWired on a private field,like this

@AutoWired
private Instrument instrument;

i was wondering ,how could spring inject an object into a private field,i know we could use reflection of java to get some meta data,when i use reflection to set a object on a private field ,here comes a problem ,following is the stacktrace

 java.lang.IllegalAccessException: Class com.wire.with.annotation.Main can not access a member of class com.wire.with.annotation.Performer with modifiers "private"

some body can explain it ? why spring could inject an object into a private field with no setter method . thanks a lot