Java: Can I create Generic-typed static classes? -

i'm working on quicksort algorithm in java, , i'm required use arrays.

right now, want make algorithm support sorting array of comparables.

i've looked around, of discussion , tutorials around generics pretty confusing. put, i'm not sure how make work. i've confirmed quicksort works integers, strings, etc, need make work comparables. ide telling me "cannot make reference non-static type t". i'm not sure means.

public class quicksort<t extends comparable<t>> {  public static void sort(t[] a) {     quicksortrecursive(a, 0, a.length-1); }  public static  void quicksortrecursive(t[] a, int p, int r) {      if( p < r ) {         int q = partition(a, p, r);         quicksortrecursive(a, p, q-1);         quicksortrecursive(a, q+1, r);     } }  public static int partition(t[] a, int p, int r) {     string x = a[r];      int = p - 1;     for(int j = p; j < r; j++) {         if(a[j].compareto(x) <= 0) {             = + 1;             //swap a[i] a[j]             t tmp = a[i];             a[i] = a[j];             a[j] = tmp;         }     }     //swap a[i + 1] a[r]     t tmp2 = a[i + 1];     a[i + 1] = a[r];     a[r] = tmp2;     return + 1; }  } 

in nutshell, doing wrong here?

oh ... ...

when designing generic class like

class quicksort<t extends comparable<t>> { ... } 

that means instances of class can (and should) parameterized concrete type parameters. example can declare

quicksort<string> sorter = new quicksort<>(); 

static methods not belong instances, these methods have no clue meaning of type paramater t. make static methods generic themselves:

static <t> void sort(t[] a) { ... } static <t> void quicksortrecursive(t[] a, int p, int r) { ... } static <t> int partition(t[] a, int p, int r) { ... } 

but leads other errors. example, have following line in method partition:

string x = a[r]; 

as parameter a type t[], compiler not allow assignment of array's element string typed variable (t anything). if know, these strings, why not declare

static int partition(string[] a, int p, int r) { ... } 

no need generics here.

additionally, oop objects (aka instances) , not static methods more procedural design. remove static keyword methods , change above mentioned problematic line

t x = a[r]; 

then fine , can use class following:

quicksort<string> sorter = new quicksort<>(); string[] strings = somestrings(); sorter.sort(strings); 

as side note: java code conventions method , variable names should start lower letters, better name methods sort, quicksortrecursive, , partition.