{"id":4258,"date":"2021-05-13T12:25:28","date_gmt":"2021-05-13T12:25:28","guid":{"rendered":"https:\/\/codethataint.com\/blog\/?p=4258"},"modified":"2021-05-13T14:43:42","modified_gmt":"2021-05-13T14:43:42","slug":"stream-code-interview-questions","status":"publish","type":"post","link":"https:\/\/codethataint.com\/blog\/stream-code-interview-questions\/","title":{"rendered":"Stream Code Interview Questions"},"content":{"rendered":"
    \n
  1. What is the Difference between Map and Filter?<\/strong>
    \nBoth perform intermediate Operations and returns stream as output.By using map, you transform the object values.
    \nMap <\/strong>returns a stream consisting of the results of applying the given function to the elements of this stream. In a simple sentence, the map returns the transformed object value.
    \nFilter <\/strong>is used for filtering the data, it always returns the boolean value. If it returns true, the item is added to list else it is filtered out (ignored)\n<\/li>\n
  2. Find the Sum of Nos in List?<\/strong>\n
    \r\npublic class ReduceEgs {\r\n    public static void main(String[] args) {\r\n        List<Integer> arrNumbers =  Arrays.asList(1,2,3,4,5,6,7,8,9);\r\n\r\n        Integer sum = arrNumbers.stream().reduce(0, Integer::sum);\r\n        Integer sum2 = arrNumbers.stream().reduce(0, (x,y)->x+y);\r\n        Integer sum3 = arrNumbers.stream().reduce(0, ReduceEgs::sumNos);\r\n    }\r\n\r\n    public static Integer sumNos(int x, int y){\r\n        System.out.println("a -"+ x + " b - "+  y);\r\n        return x+y;\r\n    }\r\n}\r\n<\/pre>\n<\/li>\n
  3. Find the Min and Max in Nos List?<\/strong>\n
    \r\n public static void main(String[] args) {\r\n        List<Integer> arrNumbers =  Arrays.asList(1,2,3,4,5,-6,7,-8,9);\r\n\r\n        arrNumbers =  Arrays.asList(-5,-6,-8);\r\n        Integer Max = arrNumbers.stream().reduce(0, (x,y)->x>y?x:y);\r\n        System.out.println("Output 1 ="+ Max);\r\n\r\n        \/\/Its good to start with Identity as Negative Value in order to address negative Integer Comparison\r\n        \/\/If you start with 0 then 0 would be returned like above\r\n        Integer Max2 = arrNumbers.stream().reduce(Integer.MIN_VALUE, (x,y)->x>y?x:y);\r\n        System.out.println("Output 2 ="+ Max2);\r\n\r\n        arrNumbers =  Arrays.asList(5,6,8);\r\n\r\n        Integer Min = arrNumbers.stream().reduce(0, (x,y)->x<y?x:y);\r\n        System.out.println("Output 3 ="+ Min);\r\n\r\n        \/\/Its good to start with Identity as Max Positive Value in order to address Integer Comparison\r\n        Integer Min2 = arrNumbers.stream().reduce(Integer.MAX_VALUE, (x,y)->x<y?x:y);\r\n        System.out.println("Output 4 ="+ Min2);\r\n    }\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nOutput 1 =0\r\nOutput 2 =-5\r\nOutput 3 =0\r\nOutput 4 =5\r\n<\/pre>\n<\/li>\n
  4. Find the Sum of Square of Nos in List?<\/strong>\n
    \r\npublic class ReduceEgs {\r\n    public static void main(String[] args) {\r\n        List<Integer> arrNumbers =  Arrays.asList(1,2,3);\r\n\r\n        Integer squareSum = arrNumbers.stream().map(x->x*x).reduce(0, Integer::sum);\r\n        System.out.println("Output 1 ="+ squareSum);\r\n    }\r\n}\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nOutput 1 =14\r\n<\/pre>\n<\/li>\n
  5. Find the Sum of Odd Nos in List?<\/strong>\n
    \r\npublic class ReduceEgs {\r\n    public static void main(String[] args) {\r\n        List<Integer> arrNumbers =  Arrays.asList(1,2,3);\r\n\r\n        Integer squareSum = arrNumbers.stream().filter(x-> x%2==1).reduce(0, Integer::sum);\r\n        System.out.println("Output 1 ="+ squareSum);\r\n    }\r\n}\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nOutput 1 =4\r\n<\/pre>\n<\/li>\n
  6. Distinct elements from List?<\/strong>\n
    \r\npublic class ReduceEgs {\r\n    public static void main(String[] args) {\r\n        List<Integer> arrNumbers =  Arrays.asList(1,2,3,1,4,2);\r\n\r\n        System.out.println("Output 1");\r\n        arrNumbers.stream().distinct().forEach(System.out::println);\r\n    }\r\n}\r\n\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nOutput 1\r\n1\r\n2\r\n3\r\n4\r\n<\/pre>\n<\/li>\n
  7. Sort Elements in List?<\/strong>\n
    \r\n public static void main(String[] args) {\r\n   List<Integer> arrNumbers =  Arrays.asList(1,2,3,1,4,2);\r\n\r\n   System.out.println("Output 2");\r\n   arrNumbers.stream().sorted().forEach(System.out::println);\r\n}\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nOutput 2\r\n1\r\n1\r\n2\r\n2\r\n3\r\n4\r\n<\/pre>\n<\/li>\n
  8. Sorting based on Natural Order, Reverse Order and Length of String?<\/strong>\n
    \r\npublic static void main(String[] args) {\r\n        List<String> arrSkills = Arrays.asList("Java", "Python",  "Ant");\r\n\r\n        System.out.println("Sorting in Natural Order");\r\n        arrSkills.stream().sorted(Comparator.naturalOrder()).forEach(System.out::println);\r\n\r\n        System.out.println("Sorting in Reverse Order");\r\n        arrSkills.stream().sorted(Comparator.reverseOrder()).forEach(System.out::println);\r\n\r\n        System.out.println("Sorting based on Length");\r\n        arrSkills.stream().sorted(Comparator.comparing(str -> str.length())).forEach(System.out::println);\r\n\r\n    }\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nSorting in Natural Order\r\nAnt\r\nJava\r\nPython\r\nSorting in Reverse Order\r\nPython\r\nJava\r\nAnt\r\nSorting based on Length\r\nAnt\r\nJava\r\nPython\r\n<\/pre>\n<\/li>\n
  9. Collect the Elements in the List – Collect Even Nos and Length of String ?<\/strong>\n
    \r\n    public static void main(String[] args) {\r\n        List<Integer> arrNumbers = Arrays.asList(1,2,4,5,7,6);\r\n        List<String> arrNames = Arrays.asList("Java", "Oracle", "Maven", "Ant");\r\n\r\n        System.out.println("Collect Even Nos in list");\r\n        List<Integer> arrEvenNumbers = arrNumbers.stream().filter(x->x%2==0).collect(Collectors.toList());\r\n        arrEvenNumbers.stream().forEach(System.out::println);\r\n\r\n        System.out.println("Length of Elements");\r\n        List<Integer> arrEvenNumbers2 = arrNames.stream().map(str->str.length()).collect(Collectors.toList());\r\n        arrEvenNumbers2.stream().forEach(System.out::println);\r\n    }\r\n<\/pre>\n
    Output<\/strong><\/p>\n
    \r\nCollect Even Nos in list\r\n2\r\n4\r\n6\r\nLength of Elements\r\n4\r\n6\r\n5\r\n3\r\n<\/pre>\n<\/li>\n
  10. Find the Sum of Nos in List?<\/strong>\n
    \r\n<\/pre>\n<\/li>\n
  11. Find the Sum of Nos in List?<\/strong>\n
    \r\n<\/pre>\n<\/li>\n
  12. Find the Sum of Nos in List?<\/strong>\n
    \r\n<\/pre>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
    What is the Difference between Map and Filter? Both perform intermediate Operations and returns stream as output.By using map, you transform the object values. Map returns a stream consisting of the results of applying the given function to the elements of this stream. In a simple sentence, the map returns the transformed object value. Filter… Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[260],"tags":[],"class_list":["post-4258","post","type-post","status-publish","format-standard","hentry","category-interview-questions-java-8"],"_links":{"self":[{"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/posts\/4258","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/comments?post=4258"}],"version-history":[{"count":5,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/posts\/4258\/revisions"}],"predecessor-version":[{"id":4274,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/posts\/4258\/revisions\/4274"}],"wp:attachment":[{"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/media?parent=4258"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/categories?post=4258"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codethataint.com\/blog\/wp-json\/wp\/v2\/tags?post=4258"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}