В чём разница между main внутри класса или снаружи?

public class BasicSample : Object {

    public void run () {
        stdout.printf ("Hello World\n");
    }

    static int main (string[] args) {
        var sample = new BasicSample ();
        sample.run ();
        return 0;
    }
}

/* 1.c generated by valac 0.36.7, the Vala compiler
 * generated from 1.vala, do not modify */


#include <glib.h>
#include <glib-object.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


#define TYPE_BASIC_SAMPLE (basic_sample_get_type ())
#define BASIC_SAMPLE(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), TYPE_BASIC_SAMPLE, BasicSample))
#define BASIC_SAMPLE_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), TYPE_BASIC_SAMPLE, BasicSampleClass))
#define IS_BASIC_SAMPLE(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), TYPE_BASIC_SAMPLE))
#define IS_BASIC_SAMPLE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), TYPE_BASIC_SAMPLE))
#define BASIC_SAMPLE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), TYPE_BASIC_SAMPLE, BasicSampleClass))

typedef struct _BasicSample BasicSample;
typedef struct _BasicSampleClass BasicSampleClass;
typedef struct _BasicSamplePrivate BasicSamplePrivate;
#define _g_object_unref0(var) ((var == NULL) ? NULL : (var = (g_object_unref (var), NULL)))

struct _BasicSample {
	GObject parent_instance;
	BasicSamplePrivate * priv;
};

struct _BasicSampleClass {
	GObjectClass parent_class;
};


static gpointer basic_sample_parent_class = NULL;

GType basic_sample_get_type (void) G_GNUC_CONST;
enum  {
	BASIC_SAMPLE_0_PROPERTY
};
void basic_sample_run (BasicSample* self);
static gint basic_sample_main (gchar** args, int args_length1);
BasicSample* basic_sample_new (void);
BasicSample* basic_sample_construct (GType object_type);


void basic_sample_run (BasicSample* self) {
	FILE* _tmp0_;
	g_return_if_fail (self != NULL);
	_tmp0_ = stdout;
	fprintf (_tmp0_, "Hello World\n");
}


static gint basic_sample_main (gchar** args, int args_length1) {
	gint result = 0;
	BasicSample* sample = NULL;
	BasicSample* _tmp0_;
	_tmp0_ = basic_sample_new ();
	sample = _tmp0_;
	basic_sample_run (sample);
	result = 0;
	_g_object_unref0 (sample);
	return result;
}


int main (int argc, char ** argv) {
#if !GLIB_CHECK_VERSION (2,35,0)
	g_type_init ();
#endif
	return basic_sample_main (argv, argc);
}


BasicSample* basic_sample_construct (GType object_type) {
	BasicSample * self = NULL;
	self = (BasicSample*) g_object_new (object_type, NULL);
	return self;
}


BasicSample* basic_sample_new (void) {
	return basic_sample_construct (TYPE_BASIC_SAMPLE);
}


static void basic_sample_class_init (BasicSampleClass * klass) {
	basic_sample_parent_class = g_type_class_peek_parent (klass);
}


static void basic_sample_instance_init (BasicSample * self) {
}


GType basic_sample_get_type (void) {
	static volatile gsize basic_sample_type_id__volatile = 0;
	if (g_once_init_enter (&basic_sample_type_id__volatile)) {
		static const GTypeInfo g_define_type_info = { sizeof (BasicSampleClass), (GBaseInitFunc) NULL, (GBaseFinalizeFunc) NULL, (GClassInitFunc) basic_sample_class_init, (GClassFinalizeFunc) NULL, NULL, sizeof (BasicSample), 0, (GInstanceInitFunc) basic_sample_instance_init, NULL };
		GType basic_sample_type_id;
		basic_sample_type_id = g_type_register_static (G_TYPE_OBJECT, "BasicSample", &g_define_type_info, 0);
		g_once_init_leave (&basic_sample_type_id__volatile, basic_sample_type_id);
	}
	return basic_sample_type_id__volatile;
}

/* 2.c generated by valac 0.36.7, the Vala compiler
 * generated from 2.vala, do not modify */


#include <glib.h>
#include <glib-object.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


#define TYPE_BASIC_SAMPLE (basic_sample_get_type ())
#define BASIC_SAMPLE(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), TYPE_BASIC_SAMPLE, BasicSample))
#define BASIC_SAMPLE_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), TYPE_BASIC_SAMPLE, BasicSampleClass))
#define IS_BASIC_SAMPLE(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), TYPE_BASIC_SAMPLE))
#define IS_BASIC_SAMPLE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), TYPE_BASIC_SAMPLE))
#define BASIC_SAMPLE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), TYPE_BASIC_SAMPLE, BasicSampleClass))

typedef struct _BasicSample BasicSample;
typedef struct _BasicSampleClass BasicSampleClass;
typedef struct _BasicSamplePrivate BasicSamplePrivate;
#define _g_object_unref0(var) ((var == NULL) ? NULL : (var = (g_object_unref (var), NULL)))

struct _BasicSample {
	GObject parent_instance;
	BasicSamplePrivate * priv;
};

struct _BasicSampleClass {
	GObjectClass parent_class;
};


static gpointer basic_sample_parent_class = NULL;

GType basic_sample_get_type (void) G_GNUC_CONST;
enum  {
	BASIC_SAMPLE_0_PROPERTY
};
void basic_sample_run (BasicSample* self);
BasicSample* basic_sample_new (void);
BasicSample* basic_sample_construct (GType object_type);
gint _vala_main (gchar** args, int args_length1);


void basic_sample_run (BasicSample* self) {
	FILE* _tmp0_;
	g_return_if_fail (self != NULL);
	_tmp0_ = stdout;
	fprintf (_tmp0_, "Hello World\n");
}


BasicSample* basic_sample_construct (GType object_type) {
	BasicSample * self = NULL;
	self = (BasicSample*) g_object_new (object_type, NULL);
	return self;
}


BasicSample* basic_sample_new (void) {
	return basic_sample_construct (TYPE_BASIC_SAMPLE);
}


static void basic_sample_class_init (BasicSampleClass * klass) {
	basic_sample_parent_class = g_type_class_peek_parent (klass);
}


static void basic_sample_instance_init (BasicSample * self) {
}


GType basic_sample_get_type (void) {
	static volatile gsize basic_sample_type_id__volatile = 0;
	if (g_once_init_enter (&basic_sample_type_id__volatile)) {
		static const GTypeInfo g_define_type_info = { sizeof (BasicSampleClass), (GBaseInitFunc) NULL, (GBaseFinalizeFunc) NULL, (GClassInitFunc) basic_sample_class_init, (GClassFinalizeFunc) NULL, NULL, sizeof (BasicSample), 0, (GInstanceInitFunc) basic_sample_instance_init, NULL };
		GType basic_sample_type_id;
		basic_sample_type_id = g_type_register_static (G_TYPE_OBJECT, "BasicSample", &g_define_type_info, 0);
		g_once_init_leave (&basic_sample_type_id__volatile, basic_sample_type_id);
	}
	return basic_sample_type_id__volatile;
}


gint _vala_main (gchar** args, int args_length1) {
	gint result = 0;
	BasicSample* sample = NULL;
	BasicSample* _tmp0_;
	_tmp0_ = basic_sample_new ();
	sample = _tmp0_;
	basic_sample_run (sample);
	result = 0;
	_g_object_unref0 (sample);
	return result;
}


int main (int argc, char ** argv) {
#if !GLIB_CHECK_VERSION (2,35,0)
	g_type_init ();
#endif
	return _vala_main (argv, argc);
}

public class BasicSample : Object {

    private void privateRun () {
        stdout.printf ("Hello World\n");
    }
    static int main (string[] args) {
        var sample = new BasicSample ();
        sample.privateRun ();
        return 0;
    }
}