Don't Go, Java!

@noctarius2k
Who’s that dude?
• Chris Engelbert
• Senior Developer Advocate @ Instana
• Java-Passionate (10+ years)
• Go (2 years)
• Performance
• Garbage Collection
• Benchmark Fairytales

@noctarius2k
Who’s That Dude?
Codes Java
Prefers Kotlin
Forced to use JS
Kinda likes Go
Adores TypeScript

@noctarius2k
Who’s That Dude?
Codes Java
Prefers Kotlin
Forced to use JS
Kinda likes Go
LOVES BEER!
(German, obviously)
Adores TypeScript

@noctarius2k
Disclaimer
I actually like Go!

@noctarius2k
What Is Go?
Go: The Good Parts
1. It’s opinionated
https://www.pexels.com/photo/blank-paper-with-pen-and-coffee-cup-on-wood-table-6357/

@noctarius2k
What Is Go?
General Purpose Language
Inception: 2009
Version 1.0: 2012
Current Release: 1.11

@noctarius2k
What Is Go?
package main
func main() {
value := "my string"
}
Type Inference

@noctarius2k
What Is Go?
package main
func main() {
value := "my string"
}
Type Inference
C
om
pile
Error

@noctarius2k
What Is Go?
package main
func main() {
value := "my string”
}
Type Inference
C
om
pile
Error

@noctarius2k
What Is Go?
package main
import "io/ioutil"
func main() {
}
Extensive Stdlib

@noctarius2k
What Is Go?
package main
import "io/ioutil"
func main() {
}
Extensive Stdlib
C
om
pile
Error

@noctarius2k
What Is Go?
func main() {
x, y := findCoordinates("conference")
}
func findCoordinates(place string) (x, y int) {
return 0, 0
}
Multi-Value Return

@noctarius2k
What Is Go?
package main
import "os"
func main() {
file, _ := os.Open("/tmp/foo")
defer file.Close()
}
Automatic Resource Management

@noctarius2k
What else is ?
Unfortunately!

@noctarius2k
What Is Go too? - Unfortunately
Error Handling
func main() {
file, err := os.Open("/tmp/foo")
if err != nil {
log.Fatal(err)
}
defer file.Close()
}

@noctarius2k
Error Handling
func foo() error {
file, err := os.Open("/tmp/foo")
if err != nil {
return err
}
defer file.Close()
return nil
}

@noctarius2k
Public Vs. (Package) Private
func Foo() {
}
func foo() {
}

@noctarius2k
func Foo() {
}
func foo() {
}
public
private

@noctarius2k
func ⽇日本語() {
}
?

@noctarius2k
func ⽇日本語() {
}
private

@noctarius2k
Syntax
func (f *foo) method(p1 *string) (foo, error) {
if p1 == nil {
return "", errors.New("Nil pointer")
}
return "foo", nil
}

@noctarius2k
Syntax
func (f *foo(*string)) method(p1 *string) (foo, error) {
if p1 == nil {
return "", errors.New("Nil pointer")
}
return "foo", nil
}

@noctarius2k

@noctarius2k
5 Things You Can Hate About Go
But You Don’t Have To

@noctarius2k
You’re Crazy, But Don’t You Worry!

@noctarius2k
func foo(var1 string) {
for {
var1 := "bar"
fmt.Println(var1)
break
}
}
func main() {
foo("foo")
}

@noctarius2k
func foo(var1 string) {
for {
fmt := "bar"
fmt.Println(var1)
break
}
}
func main() {
foo("foo")
}

@noctarius2k
type task struct {
}
func main() {
task := &task{}
}

@noctarius2k
type task struct {
}
func main() {
task := &task{}
task = &task{}
}

@noctarius2k
Clone Or Not Clone, That Is The Question!

@noctarius2k
type handle int
func types(val interface{}) {
switch v := val.(type) {
case int:
fmt.Println(fmt.Sprintf("I am an int: %d", v))
}
case handle:
fmt.Println(fmt.Sprintf("I am an handle: %d", v))
}
}

@noctarius2k
func main() {
var var1 int = 1
var var2 handle = 2
types(var1)
types(var2)
}
type handle int
case int:
}
case handle:
}
}

@noctarius2k
func main() {
var var1 int = 1
var var2 handle = 2
types(var1)
types(var2)
}
type handle = int
case int:
}
case handle:
}
}

@noctarius2k
type Callable func()
func test(callable Callable) {
callable()
}
func main() {
myCallable := func() {
fmt.Println("callable")
}
test(myCallable)
}

@noctarius2k
type Callable func()
func main() {
callable1 := func() {
fmt.Println("callable1")
}
var callable2 Callable
callable2 = func() {
fmt.Println("callable2")
}
test(callable1)
test(callable2)
}
func test(val interface{}) {
case func():
v()
default:
fmt.Println("wrong type")
}
}

@noctarius2k
He Looks Lazy, Isn’t He?

@noctarius2k
func main() {
functions := make([]func(), 3)
for i := 0; i < 3; i++ {
functions[i] = func() {
fmt.Println(fmt.Sprintf("iterator value: %d", i))
}
}
functions[0]()
functions[1]()
functions[2]()
}

@noctarius2k
func main() {
for i := 0; i < 3; i++ {
functions[i] = func(i int) func() {
return func() {
}
}(i)
}
functions[0]()
functions[1]()
functions[2]()
}

@noctarius2k
func main() {
for i := 0; i < 3; i++ {
i := i
functions[i] = func() {
}
}
functions[0]()
functions[1]()
functions[2]()
}

@noctarius2k
Aren’t We All A Little Bit Gopher?

@noctarius2k
type Sortable interface {
Sort(other Sortable)
}

@noctarius2k
}
type MyStruct struct{}
func (m MyStruct) Sort(other Sortable) {}

@noctarius2k
}
func main() {
var foo Sortable = &MyStruct{}
foo.Sort(&MyStruct{})
}

@noctarius2k
}
var _ Sortable = MyStruct{}
var _ Sortable = (*MyStruct)(nil)

@noctarius2k
It’s Nil Or Nothing!

@noctarius2k
type MyError string
func (m MyError) Error() string {
return string(m)
}

@noctarius2k
type MyError string
return string(m)
}
type error interface {
Error() string
}

@noctarius2k
type MyError string
return string(m)
}
func test(v bool) error {
var e *MyError = nil
if v {
return nil
}
return e
}
func main() {
fmt.Println(nil == test(true))
fmt.Println(nil == test(false))
}

@noctarius2k
Seriously? I Don’t Give A FAQ!

@noctarius2k
Seriously? I Don’t Give A FAQ!
https://golang.org/doc/faq

@noctarius2k
Remember
Not Here To Scare You!

@noctarius2k
Remember
Not Here To Scare You!
But There Will Be Dragons

Don't Go, Java!

Recommended

Recommended

More Related Content

Similar to Don't Go, Java!

Similar to Don't Go, Java! (20)

More from Christoph Engelbert

More from Christoph Engelbert (20)

Recently uploaded

Recently uploaded (20)

Don't Go, Java!