多次元配列

• 宣言
  int a[][] = new int[3][5];
  int a[][] = new int[3][];
  a[0]=new int[5];
  a[1]=new int[5];
  a[2]=new int[5];
• 初期化
  int a[][] = {{1,2,3,4,5},{9,9,9},{1}}; ※非矩形でもOK
• 文字列配列
  String aa[] = new String[3];
  String aa[] = { "str1","str2","str3"};　リテラル文字列で初期化