Topics

• Getting started with Kotlin
• Extension Methods
• Java 8 Stream Equivalents
• Interfaces
• Generics
• Functions
• Idioms

Examples

• Potential Pitfall: Extensions are Resolved Statically
• Hello World
• Accumulate names in a List
• Convert elements to strings and concatenate them, separated by commas
• Compute sum of salaries of employee
• Group employees by department
• Compute sum of salaries by department
• Partition students into passing and failing
• Names of male members
• Group names of members in roster by gender
• Filter a list to another list
• Finding shortest string a list
• Different Kinds of Streams #2 - lazily using first item if exists
• Different Kinds of Streams #3 - iterate a range of Integers
• Different Kinds of Streams #4 - iterate an array, map the values, calculate the average
• Different Kinds of Streams #5 - lazily iterate a list of strings, map the values, convert to Int, find max
• Different Kinds of Streams #6 - lazily iterate a stream of Ints, map the values, print results
• Different Kinds of Streams #7 - lazily iterate Doubles, map to Int, map to String, print each
• Counting items in a list after filter is applied
• How streams work - filter, upper case, then sort a list
• Different Kinds of Streams #1 - eager using first item if it exists
• Collect example #5 - find people of legal age, output formatted string
• Collect example #6 - group people by age, print age and names together
• Collect example #7a - Map names, join together with delimiter
• Collect example #7b - Collect with SummarizingInt
• Basic Interface
• Interface with default implementations
• Declaration-site variance
• Use-site variance
• Properties in Interfaces
• Functions Taking Other Functions
• Lambda Functions
• Function References
• Basic Functions
• Shorthand Functions
• Inline Functions
• Conflicts when Implementing Multiple Interfaces with Default Implementations
• Sample extending long to render a human readable string
• Sample extending Java 7+ Path class
• Using extension functions to improve readability
• Sample extending Java 8 Temporal classes to render an ISO formatted string
• Extension functions to Companion Objects (appearance of Static functions)
• Hello World using an Object Declaration
• Hello World using a Companion Object
• Serializable and serialVersionUid in Kotlin
• Fluent methods in Kotlin