diff --git a/compiler/global/signature.ml b/compiler/global/signature.ml
index f3a6e41..2db89e8 100644
--- a/compiler/global/signature.ml
+++ b/compiler/global/signature.ml
@@ -72,3 +72,4 @@ let rec field_assoc f = function
       else field_assoc f l
 
 
+
diff --git a/compiler/obc/java/java_main.ml b/compiler/obc/java/java_main.ml
index fea7fd6..7f1ac7e 100644
--- a/compiler/obc/java/java_main.ml
+++ b/compiler/obc/java/java_main.ml
@@ -1,7 +1,9 @@
 open Misc
+open Signature
 open Java
 open Java_printer
 
+
 (** returns the vd and the pat of a fresh ident from [name] *)
 let mk_var ty name =
   let id = Idents.gen_var "java_main" name in
@@ -28,24 +30,31 @@ let program p =
       let vd_step, pat_step = mk_var Tint "step" in
       let vd_args, pat_args = mk_var (Tarray (Tclass (Names.pervasives_qn "String"), (Sint 0))) "args" in
       let body =
-        let vd_main, e_main, q_main =
-          let q_main = !Compiler_options.simulation_node |> Modules.qualify_value |> Obc2java.qualname_to_package_classe
-          in let id = Idents.gen_var "java_main" "main" in
-          mk_var_dec id (Tclass q_main), Eval (Pvar id), q_main
+        let vd_main, e_main, q_main, ty_main =
+          let q_main = !Compiler_options.simulation_node |> Modules.qualify_value in (*qual*)
+          let ty_main = (Modules.find_value q_main).node_outputs |> types_of_arg_list |> Types.prod in
+          let q_main = Obc2java.qualname_to_package_classe q_main in (*java qual*)
+          let id = Idents.gen_var "java_main" "main" in
+          mk_var_dec id (Tclass q_main), Eval (Pvar id), q_main, ty_main
         in
         let acts =
           let integer = Eval(Pclass(Names.pervasives_qn "Integer")) in
           let args1 = Eval(Parray_elem(pat_args, Sint 1)) in
           let out = Eval(Pclass(Names.qualname_of_string "java.lang.System.out")) in
+          let jarrays = Eval(Pclass(Names.qualname_of_string "java.util.Arrays")) in
+          let ret = Emethod_call(e_main, "step", []) in
+          let print_ret = match ty_main with
+            | Types.Tarray (Types.Tarray _, _) -> Emethod_call(jarrays, "deepToString", [ret])
+            | Types.Tarray _ -> Emethod_call(jarrays, "toString", [ret])
+            | _ -> Emethod_call(ret, "toString", [])
+          in
           [ Anewvar(vd_main, Enew (Tclass q_main, []));
             Aifelse( Efun(Names.pervasives_qn ">", [Eval (Pfield (pat_args, "length")); Sint 1])
                    , mk_block [Aassgn(pat_step, Emethod_call(integer, "parseInt", [args1]))]
                    , mk_block [Aassgn(pat_step, Eval (Pvar id_step_dnb))]);
             Obc2java.fresh_for (Eval pat_step)
               (fun i ->
-                [ Amethod_call(out, "printf", [ Sstring "%d => %s\\n";
-                                                Eval (Pvar i);
-                                                Emethod_call(Emethod_call(e_main, "step", []), "toString", [])])]
+                [ Amethod_call(out, "printf", [ Sstring "%d => %s\\n"; Eval (Pvar i); print_ret]) ]
               )
           ]
         in
diff --git a/lib/java/jeptagon/Pervasives.java b/lib/java/jeptagon/Pervasives.java
index f3c8f0b..35570fe 100644
--- a/lib/java/jeptagon/Pervasives.java
+++ b/lib/java/jeptagon/Pervasives.java
@@ -13,124 +13,147 @@ public class Pervasives {
 		else return i;
 	}
 
-    public static final ExecutorService executor_cached = Executors.newCachedThreadPool();
+	public static final ExecutorService executor_cached = Executors.newCachedThreadPool();
 
-    public static class StaticFuture<V> implements Future<V> {
-    	V v;
-    	
-    	public StaticFuture(V v) { this.v = v;	}
-    	
-    	public boolean cancel(boolean mayInterruptIfRunning) { return false; }
-    	
-    	public boolean isCancelled() { return false; }
-    	
-    	public boolean isDone() { return true; }
-    	
-    	public V get() { return v; }
-    	
-    	public V get(long timeout, TimeUnit unit) { return v; }	
-    }
-	
-    public static class Tuple1 {
-    	public final Object c0;
-    	public Tuple1(Object v) {
-    		c0 = v;
-    	}
-    }
-    
-    public static class Tuple2 {
-    	public final Object c0;
-    	public final Object c1;
-    	public Tuple2(Object v0, Object v1) {
-    		c0 = v0;
-    		c1 = v1;
-    	}
-    }
-    
-    public static class Tuple3 {
-    	public final Object c0;
-    	public final Object c1;
-    	public final Object c2;
-    	public Tuple3(Object v0, Object v1, Object v2) {
-    		c0 = v0;
-    		c1 = v1;
-    		c2 = v2;
-        }
-    }
-    
-    public static class Tuple4 {
-    	public final Object c0;
-    	public final Object c1;
-    	public final Object c2;
-    	public final Object c3;
-    	public Tuple4(Object v0, Object v1, Object v2, Object v3) {
-    		c0 = v0;
-    		c1 = v1;
-    		c2 = v2;
-    		c3 = v3;
-    	}
-    }
-    
-    public static class Tuple5 {
-    	public final Object c0;
-    	public final Object c1;
-    	public final Object c2;
-    	public final Object c3;
-    	public final Object c4;
-    	public Tuple5(Object v0, Object v1, Object v2, Object v3, Object v4) {
-    		c0 = v0;
-    		c1 = v1;
-    		c2 = v2;
-    		c3 = v3;
-    		c4 = v4;
-    	}
-    }
-    
-    public static class Tuple6 {
-    	public final Object c0;
-    	public final Object c1;
-    	public final Object c2;
-    	public final Object c3;
-    	public final Object c4;
-    	public final Object c5;
-    	public Tuple6(Object v0, Object v1, Object v2, Object v3, Object v4, Object v5) {
-    		c0 = v0;
-    		c1 = v1;
-    		c2 = v2;
-    		c3 = v3;
-    		c4 = v4;
-    		c5 = v5;
-    	}
-    }
-    
-    public static class Tuple7 {
-    	public final Object c0;
-    	public final Object c1;
-    	public final Object c2;
-    	public final Object c3;
-    	public final Object c4;
-    	public final Object c5;
-    	public final Object c6;
-    	public Tuple7(Object v0, Object v1, Object v2, Object v3, Object v4, Object v5, Object v6) {
-    		c0 = v0;
-    		c1 = v1;
-    		c2 = v2;
-    		c3 = v3;
-    		c4 = v4;
-    		c5 = v5;
-    		c6 = v6;
-    	}
-    }
+	public static class StaticFuture<V> implements Future<V> {
+		V v;
 
-    public static int do_stuff(int coeff) {
-        int x = 13;
-        for (int i = 0; i < coeff; i++) {
-            for (int j = 0; j < 1000000; j++) {
-                x = (x + j) % (x + j/x) + 13;
-            }
-        }
-        return x;
-    }
+		public StaticFuture(V v) { this.v = v;	}
+
+		public boolean cancel(boolean mayInterruptIfRunning) { return false; }
+
+		public boolean isCancelled() { return false; }
+
+		public boolean isDone() { return true; }
+
+		public V get() { return v; }
+
+		public V get(long timeout, TimeUnit unit) { return v; }
+	}
+
+	public static class Tuple1 {
+		public final Object c0;
+		public Tuple1(Object v) {
+			c0 = v;
+		}
+	}
+
+	public static class Tuple2 {
+		public final Object c0;
+		public final Object c1;
+		public Tuple2(Object v0, Object v1) {
+			c0 = v0;
+			c1 = v1;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString() + ")";
+		}
+	}
+
+	public static class Tuple3 {
+		public final Object c0;
+		public final Object c1;
+		public final Object c2;
+		public Tuple3(Object v0, Object v1, Object v2) {
+			c0 = v0;
+			c1 = v1;
+			c2 = v2;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString() + ", " + c2.toString() + ")";
+		}
+	}
+
+	public static class Tuple4 {
+		public final Object c0;
+		public final Object c1;
+		public final Object c2;
+		public final Object c3;
+		public Tuple4(Object v0, Object v1, Object v2, Object v3) {
+			c0 = v0;
+			c1 = v1;
+			c2 = v2;
+			c3 = v3;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString()
+			+ ", " + c2.toString() + ", " + c3.toString() + ")";
+		}
+	}
+
+	public static class Tuple5 {
+		public final Object c0;
+		public final Object c1;
+		public final Object c2;
+		public final Object c3;
+		public final Object c4;
+		public Tuple5(Object v0, Object v1, Object v2, Object v3, Object v4) {
+			c0 = v0;
+			c1 = v1;
+			c2 = v2;
+			c3 = v3;
+			c4 = v4;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString() + ", " + c2.toString()
+			+ ", " + c3.toString() + ", " + c4.toString() + ")";
+		}
+	}
+
+	public static class Tuple6 {
+		public final Object c0;
+		public final Object c1;
+		public final Object c2;
+		public final Object c3;
+		public final Object c4;
+		public final Object c5;
+		public Tuple6(Object v0, Object v1, Object v2, Object v3, Object v4, Object v5) {
+			c0 = v0;
+			c1 = v1;
+			c2 = v2;
+			c3 = v3;
+			c4 = v4;
+			c5 = v5;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString() + ", " + c2.toString()
+			+ ", " + c3.toString() + ", " + c4.toString() + ", " + c5.toString() + ")";
+		}
+	}
+
+	public static class Tuple7 {
+		public final Object c0;
+		public final Object c1;
+		public final Object c2;
+		public final Object c3;
+		public final Object c4;
+		public final Object c5;
+		public final Object c6;
+		public Tuple7(Object v0, Object v1, Object v2, Object v3, Object v4, Object v5, Object v6) {
+			c0 = v0;
+			c1 = v1;
+			c2 = v2;
+			c3 = v3;
+			c4 = v4;
+			c5 = v5;
+			c6 = v6;
+		}
+		public String toString() {
+			return "(" + c0.toString() + ", " + c1.toString() + ", " + c2.toString()
+			+ ", " + c3.toString() + ", " + c4.toString() + ", " + c5.toString()
+			+ ", " + c6.toString() + ")";
+		}
+	}
+
+	public static int do_stuff(int coeff) {
+		int x = 13;
+		for (int i = 0; i < coeff; i++) {
+			for (int j = 0; j < 1000000; j++) {
+				x = (x + j) % (x + j/x) + 13;
+			}
+		}
+		return x;
+	}
 
 
 }