When Java class is instance of Serializable -

i wonder when java class instance of serializable. know class serializable if implements serializable interface. i'm trying use junit generate entity class (from kind of template) , check if serializable.

my generated class (which not implement serializable) looks like:

package test;  import javax.persistence.column; import javax.persistence.entity; import javax.persistence.table; import javax.annotation.generated; import javax.persistence.id;   @entity @table( name = mytesttabledto.table_name ) public class mytesttabledto  {     public static final string table_name = "my_test_table";      public static final string column_my_id_field = "my_id_field";     public static final string field_my_id_field = "myidfield";      @id     @column( nullable = true, length = 14, name = column_my_id_field )     private long myidfield;      public long getmyidfield()     {         return myidfield;     }      public void setmyidfield( long amyidfield )     {         this.myidfield = amyidfield;     }  } 

test below:

 file generatedfile = new file( gen_output_dir, file.separator + classname + ".java" );   asserttrue( generatedfile.getclass() instanceof serializable ); //returns true 

the result suggest generated class instance of serializable. question why? think if not implements serializable should not instance of it. searched answer couldnt find anything.

you this:

file generatedfile = new file(...); 

this created instance of class file.

generatedfile.getclass() 

this got class object file object, object of type class<file>

the documentation of file describes class:

all implemented interfaces: serializable, comparable

if you'd achieve want parse java source file see if implements serializable, should appropriate tool this, build abstract syntax tree of file in question, , extract information there.

or this, using isassignablefrom method of class class:

public boolean checkserializable(class<?> classtocheck) {     return serializable.class.isassignablefrom(classtocheck); } 

and check class itself:

boolean isserializable = checkserializable(mytesttabledto.class);