# Quick Assist

Quick assists perform local code transformations. They are invoked on a selection or a single cursor in the Java editor and use the same shortcut as quick fixes (Ctrl+1), but quick assist are usually hidden when an error is around. To show them even with errors present on the same line, press Ctrl+1 a second time.
A selection of quick assists can be assigned to a direct shortcut. By default, these are:

- Rename in file: Ctrl+2, R
- Assign to local: Ctrl+2, L
- Assign to field: Ctrl+2, F

Assign more shortcuts or change the default shortcuts on the General > Keys preference page (in the 'Source' category).
A quick assist light bulb can be turned on on the Java > Editor preference page.

Name | Code example | Invocation location
--- | --- | ---
Inverse if statement | `if (x) a(); else b();` | > | `if (!x) b(); else a();` | On 'if' statements with 'else' block
Inverse boolean expression | `a && !b` | > | `!a || b` | On a boolean expression
Remove extra parentheses | `if ((a == b) && (c != d) {}` | > | `if (a == b && c != d) {}` | On selected expressions
Add paranoidal parentheses | `if (a == b && c != d) {}` | > | `if ((a == b) && (c != d)` | On selected expressions
Join nested if statements | `if (a) { if (b) {} }` | > | `if (a && b) {}` | On a nested if statement
Swap nested if statements | `if (a) { if (b) {} }` | > | `if (b) { if (a) {} }` | On a nested if statement
Split if statement with and'ed expression | `if (a && b) {}` | > | `if (a) { if (b) {} }` | On an and'ed expression in a 'if'
Split if statement with or'd expression | `if (a || b) x();` | > | `if (a) x(); if (b) x();` | On an or'd expression in a 'if'
Inverse conditional expression | `x ? b : c` | > | `!x ? c : b` | On a conditional expression
Pull negation up | `b && c` | > | `!(!b || !c)` | On a boolean expression
Push negation down | !(`b && c)` | > | !`b || !c` | On a negated boolean expression
If-else assignment to conditional expression | `if (a) x= 1; else x= 2;` | > | `x= a ? 1 : 2;` | On an 'if' statement
If-else return to conditional expression | `if (a) return 1; else return 2;` | > | `return a ? 1 : 2;` | On an 'if' statement
Conditional expression assignment to If-else | `x= a ? 1 : 2;` | > | `if (a) x= 1; else x= 2;` | On a conditional expression
Conditional expression return to If-else | `return a ? 1 : 2;` | > | `if (a) return 1; else return 2;` | On a conditional expression
Switch to If-else | `switch (kind) { case 1: return -1; case 2: return -2; }` | > | `if (kind == 1) { return -1; } else if (kind == 2) { return -2; }` | On a statement
Add missing case statements on enums | `switch (e){ }` | > | `switch (e){ case E1: break; case E2: break; }` | On a switch statement
Exchange operands | `a + b` | > | `b + a` | On an infix operation
Cast and assign | `if (obj instanceof Vector) { }` | > | `if (obj instanceof Vector) { Vector vec= (Vector)obj;` } | on a instanceof expression in an 'if' or 'while' statement
Pick out string | `"abcdefgh"` | > | `"abc" + "de" + "fgh"` | select a part of a string literal
Convert string concatination to StringBuilder (J2SE 5.0) or StringBuffer | `"Hello " + name` | > | `StringBuilder builder= new StringBuilder(); builder.append("Hello "); builder.append(name);` | select a string literal
Convert string concatination to MessageFormat | `"Hello " + name` | > | `MessageFormat.format("Hello {0}", name);` | select a string literal
Split variable | `int i= 0;` | > | `int i; i= 0;` | On a variable with initialization
Join variable | `int i; i= 0;` | > | `int i= 0` | On a variable without initialization
Assign to variable | `foo()` | > | `X x= foo();` | On an expression statement
Extract to local | `foo(getColor());` | > | `Color color= getColor(); foo(color);` | On an expression
Assign parameter to field | `public A(int color) {}` | > | `Color fColor; public A(int color) { fColor= color; }` | On a parameter
Add finally block | `try { } catch (Expression e) { }` | > | `try { } catch (Expression e) { } finally {}` | On a try/catch statement
Add else block | `if (a) b();` | > | `if (a) b(); else { }` | On a if statement
Replace statement with block | `f (a) b();` | > | `if (a) { b(); }` | On a if statement
Invert equals | `a.equals(b)` | > | `b.equals(a)` | On a invocation of 'equals'
Array initializer to Array creation | `int[] i= { 1, 2, 3 }` | > | `int[] i= new int[] { 1, 2, 3 }` | On an array initializer
Convert to 'enhanced for loop' (J2SE 1.5) | `for (Iterator i= c.iterator();i.hasNext();) { }` | > | `for (x : c) { }` | On a for loop
Create method in super class |  |  |  | On a method declaration
Unwrap blocks | `{ a() }` | > | `a()` | On blocks, if/while/for statements
Rename in file |  |  |  | On identifiers
Extract to local variable | `a= b*8;` | > | `int x= a*8; a= x;` | On expressions
Extract to constant | `a= 8;` | > | `final static int CONST= 8; a= CONST;` | On expressions
Extract method | `int x= p * 5;` | > | `int x= getFoo(p);` | On expressions and statements
Inline local variable | `int a= 8, b= a;` | > | `int b= 8;` | On local variables
Convert local variable to field | `void foo() { int a= 8; }` | > | `int a= 8; void foo() {}` | On local variables
Convert anonymous to nested class | `new Runnable() { };` | > | `class RunnableImplementation implements Runnable { }` | On anonymous classes
Replace with getter and setter (Encapsulate Field) | `p.x;` | > | `p.getX();` | On fields

Java Editor
Quick Fix and Quick Assist

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