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00: Tree from a list & flattening it back to a list in Java

Hierarchical data with parent & child relationships are very common, and Java collection does not have a Tree data structure, hence it is a popular interview question. Further questions include tree data structure processing using recursiion & iteration. A Tree data structure can be represented as shown below. Step 1:...

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01: Can you design classes & interfaces using OO?

Q1. How would you go about designing a “farm animals” application where animals like cow, pig, horse, etc move from a barn to pasture, a stable to paddock, etc? The solution should also cater for extension into other types of animals like circus animals, wild animals, etc in the future....

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01: String parsing & date formatting – complete the given code

Q. Complete the method “changeDateFormat(String paragraph)” which takes a string input containing dates in mm/dd/yyyy format and converts them to “dd/mm/yyyy” format. For example, “My birthday is on 04/25/1980” becomes “My birthday is on 25/04/1980

A.

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01: Tree flattening example in Java

Q. Traverse the tree in depth and return a list of all passed nodes. It should handle different data types as Double, String, etc. The4 interface for the tree node is A. Tree storing numbers: Tree storing text: #1. … Read more ›...

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01: What is wrong with following Java code snippets? Auto-unboxing, switch, short circuit & exception

Auto-unboxing, switch, short circuit logical operators & exception handling are core Java basics that sometimes lead to obscure errors if not understood well & often tested in coding tests.

Q1. What is wrong with this code?

A1. compile-error at switch(i) as switch works only with “int”

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02: Scenarios based Java OO concepts & GoF design patterns – naive Template Method pattern

Extends Can you design classes & interfaces using OO?. Only experience, and asking the right questions can teach you what design pattern to use, in which scenario.

Scenario: A company named XYZ Retail is in the business of selling Books, CDs and Cosmetics.

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02: Tree structure – calculate average recursively & iteratively in Java

Q. Complete the following “TreeProcessingImpl” class ….. so that the unit tests shown below pass? Skeleton Code Unit Tests A. Solution 1: Solution 2: Using recursion for getAverage(…) and iteration for getSum(…) Key Points #1: Recursion can cause stack overflow exception if you don’t properly define an exit condition. …...

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