仅在一个测试函数中找到相同的文件路径，在其他测试函数中找不到这怎么可能？
我在eclipse中运行这些junit测试：
class KGramIndexTestTest {
@Test
void testGetTerms() {
KGramIndex kgIndex = new KGramIndex(2);
File f = new File("../test/text.txt");
try {
Reader reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
Tokenizer tok = new Tokenizer( reader, true, false, true, "../patterns.txt" );
while ( tok.hasMoreTokens() ) {
String token = tok.nextToken();
kgIndex.insert(token);
}
}catch (IOException e) {
e.printStackTrace();
}
String wildcard = "hel*o";
List<String> terms = kgIndex.getTerms(wildcard);
assertEquals(terms.size(), 1);
assertEquals(terms.get(0), "hello");
}
@Test
void testGetKGrams() {
KGramIndex kgIndex = new KGramIndex(2);
File f = new File("../test/text.txt");
try {
Reader reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
Tokenizer tok = new Tokenizer( reader, true, false, true, "../patterns.txt" );
while ( tok.hasMoreTokens() ) {
String token = tok.nextToken();
kgIndex.insert(token);
}
}catch (IOException e) {
e.printStackTrace();
}
String wildcard = "hel*o";
List<String> kGrams = kgIndex.getKGrams(wildcard);
System.out.println("The k-grams");
System.out.println(kGrams);
assertEquals(4, kGrams.size());
List<String> bigrams = new ArrayList<String>();
bigrams.add("^h");
bigrams.add("he");
bigrams.add("el");
bigrams.add("o$");
assertTrue(kGrams.containsAll(bigrams));
}
}
第二个测试函数成功，但第一个失败并生成FileNotFoundException：
这是堆栈跟踪：
java.io.FileNotFoundException: ../test/text.txt (No such file or directory)
at java.base/java.io.FileInputStream.open0(Native Method)
at java.base/java.io.FileInputStream.open(FileInputStream.java:196)
at java.base/java.io.FileInputStream.<init>(FileInputStream.java:139)
at ir.KGramIndexTestTest.testGetTerms(KGramIndexTestTest.java:25)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:389)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:167)
at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:163)
这令我感到困惑，因为两个函数都使用了相同的文件路径。如何才能在其中一个功能中找到它，并在另一个功能中正常工作？
编辑：我试图关闭reader，但它没有帮助。
编辑2：我尝试了第三种变体，但我仍然得到FileNotFoundException。有问题的行是testGetTerms中的这一行：
reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
第三种变体：
class KGramIndexTestTest {
@Test
void testGetTerms() {
KGramIndex kgIndex = new KGramIndex(2);
File f = new File("../test/text.txt");
Reader reader = null;
try {
reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
Tokenizer tok = new Tokenizer( reader, true, false, true, "../patterns.txt" );
while ( tok.hasMoreTokens() ) {
String token = tok.nextToken();
kgIndex.insert(token);
}
}catch (IOException e) {
e.printStackTrace();
}finally {
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
String wildcard = "hel*o";
List<String> terms = kgIndex.getTerms(wildcard);
assertEquals(terms.size(), 1);
assertEquals(terms.get(0), "hello");
}
@Test
void testGetKGrams() {
KGramIndex kgIndex = new KGramIndex(2);
File f = new File("../test/text.txt");
Reader reader = null;
try {
reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
Tokenizer tok = new Tokenizer( reader, true, false, true, "../patterns.txt" );
while ( tok.hasMoreTokens() ) {
String token = tok.nextToken();
kgIndex.insert(token);
}
}catch (IOException e) {
e.printStackTrace();
}finally {
try {
if(reader != null) {
reader.close();
}
}catch(IOException e) {
e.printStackTrace();
}
}
String wildcard = "hel*o";
List<String> kGrams = kgIndex.getKGrams(wildcard);
System.out.println("The k-grams");
System.out.println(kGrams);
assertEquals(4, kGrams.size());
List<String> bigrams = new ArrayList<String>();
bigrams.add("^h");
bigrams.add("he");
bigrams.add("el");
bigrams.add("o$");
assertTrue(kGrams.containsAll(bigrams));
}
}
编辑3：
我尝试使用@BeforeAll和@AfterAll，但我得到了完全相同的结果。
编辑4：
我还尝试将所有断言放在工作测试用例testKGrams中。发生的事情是先前正在运行的InputStreamReader初始化已停止工作并抛出FileNotFoundException：
更新2：
KGramIndex.java：
public class KGramIndex {
HashMap<Integer,String> id2term = new HashMap<Integer,String>();
HashMap<String,Integer> term2id = new HashMap<String,Integer>();
HashMap<String,List<KGramPostingsEntry>> index = new HashMap<String,List<KGramPostingsEntry>>();
int lastTermID = -1;
int K = 3;
public KGramIndex(int k) {
K = k;
if (k <= 0) {
System.err.println("The K-gram index can't be constructed for a negative K value");
System.exit(1);
}
}
private int generateTermID() {
return ++lastTermID;
}
public int getK() {
return K;
}
public int size() {
return index.size();
}
public ArrayList<String> getTokenKGrams(String token){
ArrayList<String> kGrams = new ArrayList<String>();
int start = 0;
int end = start+K;
int noOfKGrams = token.length() - end + 1;
String kGram;
int startCurr, endCurr;
for (int i=0; i<noOfKGrams; i++) {
startCurr = start + i;
endCurr = end + i;
kGram = token.substring(startCurr, endCurr);
kGrams.add(kGram);
}
return kGrams;
}
public List<String> getKGrams(String token) {
int index = token.indexOf("*");
if(index != -1) {
String left = "^"+token.substring(0, index);
String right = token.substring(index+1, token.length())+"$";
List<String> leftKGrams = getTokenKGrams(left);
List<String> rightKGrams = getTokenKGrams(right);
leftKGrams.addAll(rightKGrams);
return leftKGrams;
}
return getTokenKGrams(token);
}
public List<String> getTerms(String wildcard){
int index = wildcard.indexOf("*");
if(index == -1) {
throw new IllegalArgumentException("wildcard must contain a '*'.");
}
List<String> kGrams = getKGrams(wildcard);
List<String> kGramContainers = new ArrayList<String>();
List<KGramPostingsEntry> intersection = getPostings(kGrams.get(0));
List<KGramPostingsEntry> newPostings;
for(int i = 1; i<kGrams.size(); i++) {
newPostings = getPostings(kGrams.get(i));
intersection = intersect(intersection, newPostings);
}
String term;
for(KGramPostingsEntry entry : intersection) {
term = id2term.get(entry.tokenID);
kGramContainers.add(term);
}
StringBuilder regexBuilder = new StringBuilder(wildcard);
regexBuilder.insert(index, ".");
String regex = regexBuilder.toString();
List<String> result = new ArrayList<String>();
for (int i=0; i<kGramContainers.size(); i++) {
term = kGramContainers.get(i);
boolean matches = Pattern.matches(regex, term);
if(matches) {
result.add(term);
}
}
return result;
}
private List<KGramPostingsEntry> intersect(List<KGramPostingsEntry> pA, List<KGramPostingsEntry> pB) {
ListIterator<KGramPostingsEntry> iterA = pA.listIterator();
ListIterator<KGramPostingsEntry> iterB = pB.listIterator();
List<KGramPostingsEntry> result = new ArrayList<KGramPostingsEntry>();
KGramPostingsEntry entryA = iterA.next();
KGramPostingsEntry entryB = iterB.next();
while(true) {
if(entryA.tokenID == entryB.tokenID) {
result.add(entryA);
if(iterA.hasNext() && iterB.hasNext()) {
entryA = iterA.next();
entryB = iterB.next();
}else {
break;
}
}else if(entryA.tokenID > entryB.tokenID) {
if(iterB.hasNext())
entryB = iterB.next();
else
break;
}
else {
if(iterA.hasNext())
entryA = iterA.next();
else
break;
}
}
return result;
}
public void insert( String token ) {
if (term2id.get(token) != null) {
return;
}
id2term.put(++lastTermID, token);
term2id.put(token, lastTermID);
// is word long enough? for example, "a" can be bigrammed and trigrammed but not four-grammed.
// K must be <= token.length + 2. "ab". K must be <= 4
List<KGramPostingsEntry> postings = null;
if(K > token.length() + 2) {
return;
}else if(K == token.length() + 2) {
// insert the one K-gram "^<String token>$" into index
postings = index.get("^"+token+"$");
if (postings == null) {
KGramPostingsEntry newEntry = new KGramPostingsEntry(lastTermID);
ArrayList<KGramPostingsEntry> newList = new ArrayList<KGramPostingsEntry>();
newList.add(newEntry);
index.put("^"+token+"$", newList);
}
// No need to do anything if the posting already exists, so no else clause. There is only one possible term in this case
// Return since we are done
return;
}else {
// We get here if there is more than one k-gram in our term
// insert all k-grams in token into index
int start = 0;
int end = start+K;
//add ^ and $ to token.
token = "^"+token+"$";
int noOfKGrams = token.length() - end + 1;
// get K-Grams
String kGram;
int startCurr, endCurr;
for (int i=0; i<noOfKGrams; i++) {
startCurr = start + i;
endCurr = end + i;
kGram = token.substring(startCurr, endCurr);
postings = index.get(kGram);
KGramPostingsEntry newEntry = new KGramPostingsEntry(lastTermID);
// if this k-gram has been seen before
if (postings != null) {
// Add this token to the existing postingsList.
// We can be sure that the list doesn't contain the token
// already, else we would previously have terminated the
// execution of this function.
int lastTermInPostings = postings.get(postings.size()-1).tokenID;
if (lastTermID == lastTermInPostings) {
continue;
}
postings.add(newEntry);
index.put(kGram, postings);
}
// if this k-gram has not been seen before
else {
ArrayList<KGramPostingsEntry> newList = new ArrayList<KGramPostingsEntry>();
newList.add(newEntry);
index.put(kGram, newList);
}
}
}
}
/** Get postings for the given k-gram */
public List<KGramPostingsEntry> getPostings(String kgram) {
return index.get(kgram);
}
/** Get id of a term */
public Integer getIDByTerm(String term) {
return term2id.get(term);
}
/** Get a term by the given id */
public String getTermByID(Integer id) {
return id2term.get(id);
}
private static HashMap<String,String> decodeArgs( String[] args ) {
HashMap<String,String> decodedArgs = new HashMap<String,String>();
int i=0, j=0;
while ( i < args.length ) {
if ( "-p".equals( args[i] )) {
i++;
if ( i < args.length ) {
decodedArgs.put("patterns_file", args[i++]);
}
}
else if ( "-f".equals( args[i] )) {
i++;
if ( i < args.length ) {
decodedArgs.put("file", args[i++]);
}
}
else if ( "-k".equals( args[i] )) {
i++;
if ( i < args.length ) {
decodedArgs.put("k", args[i++]);
}
}
else if ( "-kg".equals( args[i] )) {
i++;
if ( i < args.length ) {
decodedArgs.put("kgram", args[i++]);
}
}
else {
System.err.println( "Unknown option: " + args[i] );
break;
}
}
return decodedArgs;
}
public static void main(String[] arguments) throws FileNotFoundException, IOException {
HashMap<String,String> args = decodeArgs(arguments);
int k = Integer.parseInt(args.getOrDefault("k", "3"));
KGramIndex kgIndex = new KGramIndex(k);
File f = new File(args.get("file"));
Reader reader = new InputStreamReader( new FileInputStream(f), StandardCharsets.UTF_8 );
Tokenizer tok = new Tokenizer( reader, true, false, true, args.get("patterns_file") );
while ( tok.hasMoreTokens() ) {
String token = tok.nextToken();
kgIndex.insert(token);
}
System.out.printf("Done with indexing. %d k-grams in index\n", kgIndex.size());
String[] kgrams = args.get("kgram").split(" ");
List<KGramPostingsEntry> postings = null;
for (String kgram : kgrams) {
if (kgram.length() != k) {
System.err.println("Cannot search k-gram index: " + kgram.length() + "-gram provided instead of " + k + "-gram");
System.exit(1);
}
if (postings == null) {
System.out.println("getting postings...");
postings = kgIndex.getPostings(kgram);
} else {
postings = kgIndex.intersect(postings, kgIndex.getPostings(kgram));
}
}
if (postings == null) {
System.err.println("Found 0 posting(s)");
} else {
int resNum = postings.size();
System.err.println("Found " + resNum + " posting(s)");
if (resNum > 10) {
System.err.println("The first 10 of them are:");
resNum = 10;
}
for (int i = 0; i < resNum; i++) {
System.err.println(kgIndex.getTermByID(postings.get(i).tokenID));
System.out.println();
}
}
}
}
Tokenizer.java：
package ir;
import java.io.Reader;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.regex.PatternSyntaxException;
import java.lang.System;
/**
* This class performs tokenization of UTF-8 encoded text files.
*/
public class Tokenizer {
/**
* This flag should be set to 'true' if all letters should be
* turned into lowercase.
*/
public boolean case_folding = true;
/**
* This flag should be set to 'true' if all diacritics (accents etc.)
* should be removed.
*/
public boolean remove_diacritics = true;
/**
* This flag should be set to 'true' if all punctuation (full stops etc.)
* should be removed.
*/
public boolean remove_punctuation = true;
/**
* The size of the buffer should be considerably larger than
* the anticipated length of the longest token.
*/
public static final int BUFFER_LENGTH = 100001;
/** The reader from where tokens are read. */
Reader reader;
/**
* Characters are read @code{BUFFER_LENGTH} characters at a
* time into @code{buf}.
*/
char[] buf = new char[BUFFER_LENGTH];
/** The current position in the buffer. */
int ptr = 0;
/** Starting position of current token, or -1 if we're between tokens. */
int token_start = -1;
/** The next tokens to emit. */
ArrayList<String> token_queue = new ArrayList<String>();
/** @code{true} if we've started reading tokens. */
boolean started_reading = false;
/** The patterns matching non-standard words (e-mail addresses, etc.) */
ArrayList<Pattern> patterns = null;
/** Special characters (with diacritics) can be translated into these characters. */
public static final char[] SPECIAL_CHAR_MAPPING = {
'A', 'A', 'A', 'A', 'A', 'A', 'E', 'C', 'E', 'E', 'E', 'E', 'I', 'I', 'I', 'I', 'D', 'N', 'O', 'O', 'O', 'O', 'O', '*', 'O', 'U', 'U', 'U', 'U', 'Y', 'T', 'S', 'a', 'a', 'a', 'a', 'a', 'a', 'e', 'c', 'e', 'e', 'e', 'e', 'i', 'i', 'i', 'i', 'd', 'n', 'o', 'o', 'o', 'o', 'o', '/', 'o', 'u', 'u', 'u', 'u', 'y', 't', 'y', 'A', 'a', 'A', 'a', 'A', 'a', 'C', 'c', 'C', 'c', 'C', 'c', 'C', 'c', 'D', 'd', 'E', 'e', 'E', 'e', 'E', 'e', 'E', 'e', 'E', 'e', 'G', 'g', 'G', 'g', 'G', 'g', 'G', 'g', 'H', 'h', 'H', 'h', 'I', 'i', 'I', 'i', 'I', 'i', 'I', 'i', 'I', 'i', 'J', 'j', 'J', 'j', 'K', 'k', 'k', 'L', 'l', 'L', 'l', 'L', 'l', 'L', 'l', 'L', 'l', 'N', 'n', 'N', 'n', 'N', 'n', 'n', 'N', 'n', 'O', 'o', 'O', 'o', 'O', 'o', 'O', 'o', 'R', 'r', 'R', 'r', 'R', 'r', 'S', 's', 'S', 's', 'S', 's', 'S', 's', 'T', 't', 'T', 't', 'T', 't', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'W', 'w', 'Y', 'y', 'Y', 'Z', 'z', 'Z', 'z', 'Z', 'z' };
/* ------------------------------ */
/**
* Constructor
* @param reader The reader from which to read the text to be tokenized.
* @param case_folding Should be set to <code>true</code> if every character
* should be translated into its lowercase counterpart.
* @param remove_diacritics Should be set to <code>true</code> if diacritics
* should be removed (e.g. é will be e).
* @param remove_punctuation Should be set to <code>true</code> if punctuation
* should be removed (useful in some applications).
* @param pattern_file The name of the file containing regular expressions
* for non-standard words (like dates, mail addresses, etc.).
*/
public Tokenizer( Reader reader, boolean case_folding, boolean remove_diacritics, boolean remove_punctuation, String pattern_file ) {
this.reader = reader;
this.case_folding = case_folding;
this.remove_diacritics = remove_diacritics;
this.remove_punctuation = remove_punctuation;
if ( pattern_file != null ) {
readPatterns( pattern_file );
}
}
/**
* Returns true if the character is a punctuation character.
*/
public boolean punctuation( char c ) {
if ( c >= 32 && c <= 47 )
return true;
if ( c >= 58 && c <= 64 )
return true;
if ( c >= 91 && c <= 96 )
return true;
if ( c >= 123 && c <= 126 )
return true;
return false;
}
/**
* Read the patterns that match non-standard words
*/
private void readPatterns( String filename ) {
patterns = new ArrayList<Pattern>();
String line = null;
try {
BufferedReader in = new BufferedReader( new FileReader( filename ));
while (( line = in.readLine()) != null ) {
line = line.trim();
if ( !line.startsWith( "//" ) && line.length() > 0 ) {
patterns.add( Pattern.compile( line ));
}
}
}
catch ( IOException e ) {
System.err.println( "Warning: IOException reading the regular expressions from file" );
}
catch ( PatternSyntaxException e ) {
System.err.println( "ERROR: Malformed regular expression: " + line );
}
}
/**
* Normalizes letters by converting to lower-case and possibly
* removing diacritics. This method is also used for checking
* whether a character can occur in a token or not.
*
* @return code{true} if the (normalized counterpart of the) character
* can occur within a token, and @code{false} otherwise.
*/
public boolean normalize( char[] buf, int ptr ) {
char c = buf[ptr];
if ( Character.isLetter( c )) {
if ( remove_diacritics ) {
// Remove diacritics by mapping to the closest character
// without diacritics.
if ( c >= '\u00c0' && c <= '\u017e' ) {
buf[ptr] = SPECIAL_CHAR_MAPPING[(int)(c-'\u00c0')];
}
}
if ( case_folding ) {
buf[ptr] = Character.toLowerCase( buf[ptr] );
}
return true;
}
if ( c >= '!' && c <= '~' ) {
return true;
}
// This is not a character that can occur in a token.
return false;
}
/**
* @return the @code{true} if there are more tokens to be
* read, and @code{false} otherwise.
*/
public boolean hasMoreTokens() throws IOException {
if ( !started_reading ) {
readTokens();
started_reading = true;
}
if ( token_queue.size() == 0 )
return readTokens();
else
return true;
}
/**
* @return a String containing the next token, or @code{null} if there
* are no more tokens.
*/
public String nextToken() throws IOException {
if ( token_queue.size() == 0 ) {
if ( readTokens() )
return token_queue.remove( 0 );
else
return null;
}
else {
return token_queue.remove( 0 );
}
}
/**
* Reads the next token.
*/
private boolean readTokens() throws IOException {
if ( !started_reading ) {
refillBuffer( 0 );
started_reading = true;
}
boolean token_added_to_queue = false;
while ( buf[ptr] != 0 ) {
if ( token_start < 0 ) {
if ( normalize( buf, ptr )) {
// A token starts here
token_start = ptr;
}
ptr++;
}
else {
if ( normalize( buf, ptr )) {
// We're in the middle of a token
ptr++;
}
else {
// Check for non-standard words
token_added_to_queue = addTokensToQueue();
token_start = -1;
ptr++;
}
}
if ( ptr == BUFFER_LENGTH ) {
// The buffer has been read, so refill it
if ( token_start >= 0 ) {
// We're in the middle of a token. Copy the parts
// of the token we have read already into the
// beginning of the buffer.
System.arraycopy( buf, token_start, buf, 0, BUFFER_LENGTH-token_start );
refillBuffer( BUFFER_LENGTH-token_start );
ptr = BUFFER_LENGTH-token_start;
token_start = 0;
}
else {
refillBuffer( 0 );
ptr = 0;
}
}
if ( token_added_to_queue ) {
return true;
}
}
// We have reached end of input.
return false;
}
/**
* Adds token to the queue
*/
private boolean addTokensToQueue() {
if ( token_start < 0 ) {
return false;
}
String s = new String( buf, token_start, ptr-token_start );
if ( patterns != null ) {
// Now let's see if the string s matches one of the patterns
// for non-standard words
for ( Pattern p : patterns ) {
Matcher m = p.matcher( s );
if ( m.find() ) {
// The string contains a non-standard word. First check the prefix
// before the matching substring, then add the non-standard word
// to the token queue, then check the remainder of the string.
addStandardTokensToQueue( s.substring(0, m.start() ));
token_queue.add( m.group() );
token_start += m.end();
addTokensToQueue();
return true;
}
}
}
// This string contains only standard words
return addStandardTokensToQueue( s );
}
/**
* Adds standard tokens (i.e. tokens not matching any regular
* expression) to the queue.
*/
private boolean addStandardTokensToQueue( String s ) {
// This string s does not match any specific pattern.
// Then split it, considering all punctuation symbols
// to be separators.
boolean tokens_found = false;
StringBuffer smallbuf = new StringBuffer();
for ( int i=0; i<s.length(); i++ ) {
if ( punctuation( s.charAt( i ))) {
// The string before the punctuation sign is a token
// unless it is empty
String t = smallbuf.toString();
if ( t.length()>0 ) {
token_queue.add( t );
smallbuf = new StringBuffer();
tokens_found = true;
}
if ( !remove_punctuation ) {
token_queue.add( "" + s.charAt( i ));
tokens_found = true;
}
}
else {
smallbuf.append( s.charAt( i ));
}
}
// The string after the last punctuation sign is a token
// unless it is empty
String t = smallbuf.toString();
if ( t.length()>0 ) {
token_queue.add( t );
tokens_found = true;
}
return tokens_found;
}
/**
* Refills the buffer and adds end_of_file "\0" at the appropriate place.
*/
private void refillBuffer( int start ) throws IOException {
int chars_read = reader.read( buf, start, BUFFER_LENGTH-start );
if ( chars_read >= 0 && chars_read < BUFFER_LENGTH-start ) {
buf[chars_read] = 0;
}
}
}
2 个答案:
答案 0 :(得分：0)
在finally块
中的两个方法中关闭fileinputstream答案 1 :(得分：0)
当第一个测试用例testGetTerms打开要读取的文件时。由于某些安全原因，第二个测试用例无法打开文件。这就是它抛出fileNotFound异常的原因。根据oracle文档如下：
**FileInputStream**
public FileInputStream(String name)
throws FileNotFoundException
Creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the file system.
创建一个新的FileDescriptor对象来表示此文件连接。 首先，如果有安全管理器，则调用其checkRead方法，并将name参数作为其参数。
If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a `FileNotFoundException` is thrown.
Parameters:
name - the system-dependent file name.
Throws:
FileNotFoundException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
SecurityException - if a security manager exists and its checkRead method denies read access to the file.
See Also:
SecurityManager.checkRead(java.lang.String)
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