java-add-exception-handling

This mapping has 1 multi-map group: several pairings are equally correct there. The code view shows one arbitrary valid pairing, not the only one.

A painting is a person's account of this edit as text, recorded independently of the node mapping - a rendering often has several equally defensible answers where the mapping has one. Deletions and insertions carry no position on the opposite side in a painting, so that panel draws no caret for them.

Before1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        Scanner scanner = new Scanner(new File(filename));
8        StringBuilder content = new StringBuilder();
9        while (scanner.hasNextLine()) {
10            content.append(scanner.nextLine()).append("\n");
11        }
12        scanner.close();
13        return content.toString();
14    }
15}
16

After1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        try {
8            Scanner scanner = new Scanner(new File(filename));
9            StringBuilder content = new StringBuilder();
10            while (scanner.hasNextLine()) {
11                content.append(scanner.nextLine()).append("\n");
12            }
13            scanner.close();
14            return content.toString();
15        } catch (FileNotFoundException e) {
16            System.err.println("File not found: " + filename);
17            return "";
18        }
19    }
20}
21

Before1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        Scanner scanner = new Scanner(new File(filename));
8        StringBuilder content = new StringBuilder();
9        while (scanner.hasNextLine()) {
10            content.append(scanner.nextLine()).append("\n");
11        }
12        scanner.close();
13        return content.toString();
14    }
15}
16

After1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        try {
8            Scanner scanner = new Scanner(new File(filename));
9            StringBuilder content = new StringBuilder();
10            while (scanner.hasNextLine()) {
11                content.append(scanner.nextLine()).append("\n");
12            }
13            scanner.close();
14            return content.toString();
15        } catch (FileNotFoundException e) {
16            System.err.println("File not found: " + filename);
17            return "";
18        }
19    }
20}
21

Before1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        Scanner scanner = new Scanner(new File(filename));
8        StringBuilder content = new StringBuilder();
9        while (scanner.hasNextLine()) {
10            content.append(scanner.nextLine()).append("\n");
11        }
12        scanner.close();
13        return content.toString();
14    }
15}
16

After1import java.io.File;
2import java.io.FileNotFoundException;
3import java.util.Scanner;
4
5public class FileReader {
6    public static String readFile(String filename) {
7        try {
8            Scanner scanner = new Scanner(new File(filename));
9            StringBuilder content = new StringBuilder();
10            while (scanner.hasNextLine()) {
11                content.append(scanner.nextLine()).append("\n");
12            }
13            scanner.close();
14            return content.toString();
15        } catch (FileNotFoundException e) {
16            System.err.println("File not found: " + filename);
17            return "";
18        }
19    }
20}
21

Before

program

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "io"

. "."

identifier "File"

; ";"

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "io"

. "."

identifier "FileNotFoundException"

; ";"

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "util"

. "."

identifier "Scanner"

; ";"

class_declaration

modifiers

public "public"

class "class"

identifier "FileReader"

class_body

{ "{"

method_declaration

modifiers

public "public"

static "static"

type_identifier "String"

identifier "readFile"

formal_parameters

( "("

formal_parameter

type_identifier "String"

identifier "filename"

) ")"

block any 1:2

{ "{"

local_variable_declaration

type_identifier "Scanner"

variable_declarator

identifier "scanner"

= "="

object_creation_expression

new "new"

type_identifier "Scanner"

argument_list

( "("

object_creation_expression

new "new"

type_identifier "File"

argument_list

( "("

identifier "filename"

) ")"

; ";"

local_variable_declaration

type_identifier "StringBuilder"

variable_declarator

identifier "content"

= "="

object_creation_expression

new "new"

type_identifier "StringBuilder"

argument_list

( "("

) ")"

; ";"

while_statement

while "while"

parenthesized_expression

( "("

method_invocation

identifier "scanner"

. "."

identifier "hasNextLine"

argument_list

( "("

) ")"

block

{ "{"

expression_statement (+26 nodes collapsed)

} "}"

expression_statement

method_invocation

identifier "scanner"

. "."

identifier "close"

argument_list

( "("

) ")"

; ";"

return_statement

return "return"

method_invocation

identifier "content"

. "."

identifier "toString"

argument_list

( "("

) ")"

; ";"

} "}"

After

program

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "io"

. "."

identifier "File"

; ";"

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "io"

. "."

identifier "FileNotFoundException"

; ";"

import_declaration

import "import"

scoped_identifier

identifier "java"

. "."

identifier "util"

. "."

identifier "Scanner"

; ";"

class_declaration

modifiers

public "public"

class "class"

identifier "FileReader"

class_body

{ "{"

method_declaration

modifiers

public "public"

static "static"

type_identifier "String"

identifier "readFile"

formal_parameters

( "("

formal_parameter

type_identifier "String"

identifier "filename"

) ")"

block any 1:2

{ "{"

try_statement

try "try"

block any 1:2

{ "{"

local_variable_declaration

type_identifier "Scanner"

variable_declarator

identifier "scanner"

= "="

object_creation_expression

new "new"

type_identifier "Scanner"

argument_list

( "("

object_creation_expression

new "new"

type_identifier "File"

argument_list

( "("

identifier "filename"

) ")"

; ";"

local_variable_declaration

type_identifier "StringBuilder"

variable_declarator

identifier "content"

= "="

object_creation_expression

new "new"

type_identifier "StringBuilder"

argument_list

( "("

) ")"

; ";"

while_statement

while "while"

parenthesized_expression

( "("

method_invocation

identifier "scanner"

. "."

identifier "hasNextLine"

argument_list

( "("

) ")"

block

{ "{"

expression_statement (+26 nodes collapsed)

} "}"

expression_statement

method_invocation

identifier "scanner"

. "."

identifier "close"

argument_list

( "("

) ")"

; ";"

return_statement

return "return"

method_invocation

identifier "content"

. "."

identifier "toString"

argument_list

( "("

) ")"

; ";"

} "}"

catch_clause

catch "catch"

( "("

catch_formal_parameter

catch_type

type_identifier "FileNotFoundException"

identifier "e"

) ")"

block

{ "{"

expression_statement

method_invocation

field_access

identifier "System"

. "."

identifier "err"

. "."

identifier "println"

argument_list

( "("

binary_expression

string_literal

" "\""

string_fragment "File not found: "

" "\""

+ "+"

identifier "filename"

) ")"

; ";"

return_statement

return "return"

string_literal

" "\""

; ";"

} "}"