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Java Java Data Structures Exploring the Java Collection Framework Maps

Rohit Tolawat
Rohit Tolawat
8,277 Points

What is java.lang.reflect.InvocationTargetException ?

public Map<String,Integer> getCategoryCounts(){ Map<String,Integer> resultMap = new HashMap<String,Integer>(); for(BlogPost blogPost:getPosts()){ String blogPostCategory = blogPost.getCategory(); resultMap.put(blogPostCategory,resultMap.get(blogPostCategory) + 1); } return resultMap; }

//Got java.lang.reflect.InvocationTargetException when I ran this code

/* Thought of a workaround and it worked. But still could not understand the significance of the exception. Was it because I was adding the resultMap.get(blogPostCategory) + 1 value to a null for the category at first. */

// This was the workAround public Map<String,Integer> getCategoryCounts(){ Map<String,Integer> resultMap = new HashMap<String,Integer>(); for(BlogPost blogPost:getPosts()){ String blogPostCategory = blogPost.getCategory(); if(!resultMap.containsKey(blogPostCategory) resultMap.put(blogPostCategory,1); else resultMap.put(blogPostCategory,resultMap.get(blogPostCategory) + 1); } return resultMap; }

// Also explain the exception and its significance mentioned in the title.... Appreciate it