Figure 2.18, “Concrete Syntax for Global Variable Declaration” presents the concrete syntax for global variable declarations. Global variables are accessible by any thread, function, or functional expression. If the global initialization is specified in a global variable declaration, then the global variable has the value specified by the literal in the initial state of the model. If the transient modifier is used, then the global variable is not stored in the state vector.

Namespace. The namespace for global variables is the global namespace that is shared with constants, enumerations, records, extensions, type-aliases, threads and functions, virtual tables, and functional expressions.

Examples. 

              
  int n1; // int global variable
  int n2 := 5; // int global variable
  int wrap (0, 255) m1; // int wrap (0, 255) global variable
  int wrap (0, 255) m2 := (int wrap (0, 255)) 5; // int wrap (0, 255) global variable
  long l1; // long global variable
  long l2 := 5L; // long global variable
  long l3 := 5l; // long global variable
  long l4 := -5L; // long global variable
  long l5 := -5l; // long global variable
  float f1; // float global variable
  float f2 := 1.0F; // float global variable
  float f3 := 1.0f; // float global variable
  float f4 := -1.0F; // float global variable
  float f5 := -1.0f; // float global variable
  float f6 := 1F; // float global variable
  float f7 := 1f; // float global variable
  float f8 := -1F; // float global variable
  float f9 := -1f; // float global variable
  double d1; // double global variable
  double d2 := 1.0; // double global variable
  double d3 := 1.0D; // double global variable
  double d4 := 1.0d; // double global variable
  double d5 := -1.0; // double global variable
  double d6 := -1.0D; // double global variable
  double d7 := -1.0d; // double global variable
  double d8 := 1D; // double global variable
  double d9 := 1d; // double global variable
  double d10 := -1D; // double global variable
  double d11 := -1d; // double global variable
  int c := 'c'; // char/int global variable
  boolean b1 := true; // boolean global variable
  boolean b2 := false; // boolean global variable
  string s1 := null; // string global variable
  string s2 := "s"; // string global variable
    

Abstract Syntax Tree. 

The Java AST class for global variable declaration is the Global class.