求教：（冒号）的用法

public class GradeList {
public static void main(String[] args) {
HashMap<String,Integer> grade = new HashMap<String,Integer>();
grade.put("张三", 80);
grade.put("李四",90);
grade.put("王五",62);
grade.put("钱六",70);
for(Map.Entry<String,Integer> e : grade.entrySet())
{  
System.out.println(e.getKey()+"的成绩是"+e.getValue());
}

public class GradeList {
public static void main(String[] args) {
HashMap<String,Integer> grade = new HashMap<String,Integer>();
grade.put("张三", 80);
grade.put("李四",90);
grade.put("王五",62);
grade.put("钱六",70);
for(Map.Entry<String,Integer> e : grade.entrySet())
{  
System.out.println(e.getKey()+"的成绩是"+e.getValue());
}


这一句怎么理解for(Map.Entry<String,Integer> e : grade.entrySet())？
冒号是什么意思？