diff --git a/algorithms/roundUpToHundred/.gitignore b/algorithms/roundUpToHundred/.gitignore new file mode 100644 index 0000000000..ae3c172604 --- /dev/null +++ b/algorithms/roundUpToHundred/.gitignore @@ -0,0 +1 @@ +/bin/ diff --git a/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundred.java b/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundred.java new file mode 100644 index 0000000000..f5024c227d --- /dev/null +++ b/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundred.java @@ -0,0 +1,20 @@ +package com.java.src; + +import java.util.Scanner; + +public class RoundUpToHundred { + + public static void main(String[] args) { + Scanner scanner = new Scanner(System.in); + double input = scanner.nextDouble(); + scanner.close(); + + RoundUpToHundred.round(input); + } + + static long round(double input) { + long i = (long) Math.ceil(input); + return ((i + 99) / 100) * 100; + }; + +} diff --git a/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundredTest.java b/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundredTest.java new file mode 100644 index 0000000000..f35a9a249f --- /dev/null +++ b/algorithms/roundUpToHundred/src/com/java/src/RoundUpToHundredTest.java @@ -0,0 +1,14 @@ +package com.java.src; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class RoundUpToHundredTest { + @Test + public void givenInput_whenRound_thenRoundUpToTheNearestHundred() { + assertEquals("Rounded up to hundred", 100, RoundUpToHundred.round(99)); + assertEquals("Rounded up to three hundred ", 300, RoundUpToHundred.round(200.2)); + assertEquals("Returns same rounded value", 400, RoundUpToHundred.round(400)); + } +} diff --git a/core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java b/core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java index 7968967679..6a020f5eae 100644 --- a/core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java +++ b/core-java-io/src/test/java/com/baeldung/file/FileOperationsManualTest.java @@ -1,6 +1,7 @@ package com.baeldung.file; import org.apache.commons.io.FileUtils; +import org.apache.commons.io.IOUtils; import org.hamcrest.CoreMatchers; import org.hamcrest.Matchers; import org.junit.Test; @@ -120,4 +121,14 @@ public class FileOperationsManualTest { return resultStringBuilder.toString(); } + + @Test + public void givenFileName_whenUsingIOUtils_thenFileData() throws IOException { + String expectedData = "This is a content of the file"; + + FileInputStream fis = new FileInputStream("src/test/resources/fileToRead.txt"); + String data = IOUtils.toString(fis, "UTF-8"); + + assertEquals(expectedData, data.trim()); + } } \ No newline at end of file diff --git a/core-java/src/main/java/com/baeldung/heapdump/HeapDump.java b/core-java/src/main/java/com/baeldung/heapdump/HeapDump.java new file mode 100644 index 0000000000..8cce20de8d --- /dev/null +++ b/core-java/src/main/java/com/baeldung/heapdump/HeapDump.java @@ -0,0 +1,25 @@ +package com.baeldung.heapdump; + +import com.sun.management.HotSpotDiagnosticMXBean; + +import javax.management.MBeanServer; + +import java.io.IOException; +import java.lang.management.ManagementFactory; +import java.nio.file.Paths; + +public class HeapDump { + + public static void dumpHeap(String filePath, boolean live) throws IOException { + MBeanServer server = ManagementFactory.getPlatformMBeanServer(); + HotSpotDiagnosticMXBean mxBean = ManagementFactory.newPlatformMXBeanProxy( + server, "com.sun.management:type=HotSpotDiagnostic", HotSpotDiagnosticMXBean.class); + mxBean.dumpHeap(filePath, live); + } + + public static void main(String[] args) throws IOException { + String file = Paths.get("dump.hprof").toFile().getPath(); + + dumpHeap(file, true); + } +} diff --git a/core-java/src/main/java/com/baeldung/passwordhashing/PBKDF2Hasher.java b/core-java/src/main/java/com/baeldung/passwordhashing/PBKDF2Hasher.java new file mode 100644 index 0000000000..e2259e4249 --- /dev/null +++ b/core-java/src/main/java/com/baeldung/passwordhashing/PBKDF2Hasher.java @@ -0,0 +1,149 @@ +package com.baeldung.passwordhashing; + +import java.security.NoSuchAlgorithmException; +import java.security.SecureRandom; +import java.security.spec.InvalidKeySpecException; +import java.security.spec.KeySpec; +import java.util.Arrays; +import java.util.Base64; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +import javax.crypto.SecretKeyFactory; +import javax.crypto.spec.PBEKeySpec; + +/** + * Hash passwords for storage, and test passwords against password tokens. + * + * Instances of this class can be used concurrently by multiple threads. + * + * @author erickson + * @see StackOverflow + */ +public final class PBKDF2Hasher +{ + + /** + * Each token produced by this class uses this identifier as a prefix. + */ + public static final String ID = "$31$"; + + /** + * The minimum recommended cost, used by default + */ + public static final int DEFAULT_COST = 16; + + private static final String ALGORITHM = "PBKDF2WithHmacSHA1"; + + private static final int SIZE = 128; + + private static final Pattern layout = Pattern.compile("\\$31\\$(\\d\\d?)\\$(.{43})"); + + private final SecureRandom random; + + private final int cost; + + public PBKDF2Hasher() + { + this(DEFAULT_COST); + } + + /** + * Create a password manager with a specified cost + * + * @param cost the exponential computational cost of hashing a password, 0 to 30 + */ + public PBKDF2Hasher(int cost) + { + iterations(cost); /* Validate cost */ + this.cost = cost; + this.random = new SecureRandom(); + } + + private static int iterations(int cost) + { + if ((cost < 0) || (cost > 30)) + throw new IllegalArgumentException("cost: " + cost); + return 1 << cost; + } + + /** + * Hash a password for storage. + * + * @return a secure authentication token to be stored for later authentication + */ + public String hash(char[] password) + { + byte[] salt = new byte[SIZE / 8]; + random.nextBytes(salt); + byte[] dk = pbkdf2(password, salt, 1 << cost); + byte[] hash = new byte[salt.length + dk.length]; + System.arraycopy(salt, 0, hash, 0, salt.length); + System.arraycopy(dk, 0, hash, salt.length, dk.length); + Base64.Encoder enc = Base64.getUrlEncoder().withoutPadding(); + return ID + cost + '$' + enc.encodeToString(hash); + } + + /** + * Authenticate with a password and a stored password token. + * + * @return true if the password and token match + */ + public boolean checkPassword(char[] password, String token) + { + Matcher m = layout.matcher(token); + if (!m.matches()) + throw new IllegalArgumentException("Invalid token format"); + int iterations = iterations(Integer.parseInt(m.group(1))); + byte[] hash = Base64.getUrlDecoder().decode(m.group(2)); + byte[] salt = Arrays.copyOfRange(hash, 0, SIZE / 8); + byte[] check = pbkdf2(password, salt, iterations); + int zero = 0; + for (int idx = 0; idx < check.length; ++idx) + zero |= hash[salt.length + idx] ^ check[idx]; + return zero == 0; + } + + private static byte[] pbkdf2(char[] password, byte[] salt, int iterations) + { + KeySpec spec = new PBEKeySpec(password, salt, iterations, SIZE); + try { + SecretKeyFactory f = SecretKeyFactory.getInstance(ALGORITHM); + return f.generateSecret(spec).getEncoded(); + } + catch (NoSuchAlgorithmException ex) { + throw new IllegalStateException("Missing algorithm: " + ALGORITHM, ex); + } + catch (InvalidKeySpecException ex) { + throw new IllegalStateException("Invalid SecretKeyFactory", ex); + } + } + + /** + * Hash a password in an immutable {@code String}. + * + *
Passwords should be stored in a {@code char[]} so that it can be filled
+ * with zeros after use instead of lingering on the heap and elsewhere.
+ *
+ * @deprecated Use {@link #hash(char[])} instead
+ */
+ @Deprecated
+ public String hash(String password)
+ {
+ return hash(password.toCharArray());
+ }
+
+ /**
+ * Authenticate with a password in an immutable {@code String} and a stored
+ * password token.
+ *
+ * @deprecated Use {@link #checkPassword(char[],String)} instead.
+ * @see #hash(String)
+ */
+ @Deprecated
+ public boolean checkPassword(String password, String token)
+ {
+ return checkPassword(password.toCharArray(), token);
+ }
+
+}
diff --git a/core-java/src/main/java/com/baeldung/passwordhashing/SHA512Hasher.java b/core-java/src/main/java/com/baeldung/passwordhashing/SHA512Hasher.java
new file mode 100644
index 0000000000..4f5337f963
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/passwordhashing/SHA512Hasher.java
@@ -0,0 +1,35 @@
+package com.baeldung.passwordhashing;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+
+/** A really simple SHA_512 Encryption example.
+ *
+ */
+public class SHA512Hasher {
+
+ public String hash(String passwordToHash, byte[] salt){
+ String generatedPassword = null;
+ try {
+ MessageDigest md = MessageDigest.getInstance("SHA-512");
+ md.update(salt);
+ byte[] bytes = md.digest(passwordToHash.getBytes(StandardCharsets.UTF_8));
+ StringBuilder sb = new StringBuilder();
+ for(int i=0; i< bytes.length ;i++){
+ sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
+ }
+ generatedPassword = sb.toString();
+ }
+ catch (NoSuchAlgorithmException e){
+ e.printStackTrace();
+ }
+ return generatedPassword;
+ }
+
+ public boolean checkPassword(String hash, String attempt, byte[] salt){
+ String generatedHash = hash(attempt, salt);
+ return hash.equals(generatedHash);
+ }
+}
diff --git a/core-java/src/main/java/com/baeldung/passwordhashing/SimplePBKDF2Hasher.java b/core-java/src/main/java/com/baeldung/passwordhashing/SimplePBKDF2Hasher.java
new file mode 100644
index 0000000000..36c9b65070
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/passwordhashing/SimplePBKDF2Hasher.java
@@ -0,0 +1,18 @@
+package com.baeldung.passwordhashing;
+
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.spec.KeySpec;
+
+/** A really simple SimplePBKDF2 Encryption example.
+ *
+ */
+public class SimplePBKDF2Hasher {
+
+ public static String hashSimple(String password, byte[] salt) throws Exception{
+ KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 65536, 128);
+ SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
+ byte[] hash = f.generateSecret(spec).getEncoded();
+ return String.valueOf(hash);
+ }
+}
diff --git a/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java b/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java
index a22de0db18..fb92eb8d0d 100644
--- a/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java
+++ b/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetDateTimeExample.java
@@ -1,16 +1,12 @@
package com.baeldung.zoneddatetime;
-import java.time.LocalDateTime;
import java.time.OffsetDateTime;
-import java.time.ZoneId;
import java.time.ZoneOffset;
public class OffsetDateTimeExample {
- public OffsetDateTime getCurrentTimeByZoneOffset(String region) {
- LocalDateTime now = LocalDateTime.now();
- ZoneId zone = ZoneId.of(region);
- ZoneOffset zoneOffSet= zone.getRules().getOffset(now);
+ public OffsetDateTime getCurrentTimeByZoneOffset(String offset) {
+ ZoneOffset zoneOffSet= ZoneOffset.of(offset);
OffsetDateTime date = OffsetDateTime.now(zoneOffSet);
return date;
}
diff --git a/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java b/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java
index 7d926c0562..58e2d4d5ad 100644
--- a/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java
+++ b/core-java/src/main/java/com/baeldung/zoneddatetime/OffsetTimeExample.java
@@ -1,17 +1,12 @@
package com.baeldung.zoneddatetime;
-import java.time.LocalDateTime;
import java.time.OffsetTime;
-import java.time.ZoneId;
import java.time.ZoneOffset;
public class OffsetTimeExample {
- public OffsetTime getCurrentTimeByZoneOffset(String region) {
- LocalDateTime now = LocalDateTime.now();
- ZoneId zone = ZoneId.of(region);
- ZoneOffset zoneOffSet = zone.getRules()
- .getOffset(now);
+ public OffsetTime getCurrentTimeByZoneOffset(String offset) {
+ ZoneOffset zoneOffSet = ZoneOffset.of(offset);
OffsetTime time = OffsetTime.now(zoneOffSet);
return time;
}
diff --git a/core-java/src/test/java/com/baeldung/passwordhashing/PBKDF2HasherUnitTest.java b/core-java/src/test/java/com/baeldung/passwordhashing/PBKDF2HasherUnitTest.java
new file mode 100644
index 0000000000..8e90725c77
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/passwordhashing/PBKDF2HasherUnitTest.java
@@ -0,0 +1,41 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+
+public class PBKDF2HasherUnitTest {
+
+ private PBKDF2Hasher mPBKDF2Hasher;
+
+ @Before
+ public void setUp() throws Exception {
+ mPBKDF2Hasher = new PBKDF2Hasher();
+ }
+
+ @Test
+ public void givenCorrectMessageAndHash_whenAuthenticated_checkAuthenticationSucceeds() throws Exception {
+ String message1 = "password123";
+
+ String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+ assertTrue(mPBKDF2Hasher.checkPassword(message1.toCharArray(), hash1));
+
+ }
+
+ @Test
+ public void givenWrongMessage_whenAuthenticated_checkAuthenticationFails() throws Exception {
+ String message1 = "password123";
+
+ String hash1 = mPBKDF2Hasher.hash(message1.toCharArray());
+
+ String wrongPasswordAttempt = "IamWrong";
+
+ assertFalse(mPBKDF2Hasher.checkPassword(wrongPasswordAttempt.toCharArray(), hash1));
+
+ }
+
+
+}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/passwordhashing/SHA512HasherUnitTest.java b/core-java/src/test/java/com/baeldung/passwordhashing/SHA512HasherUnitTest.java
new file mode 100644
index 0000000000..3acfb0ba9d
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/passwordhashing/SHA512HasherUnitTest.java
@@ -0,0 +1,70 @@
+package com.baeldung.passwordhashing;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.security.SecureRandom;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by PhysicsSam on 06-Sep-18.
+ */
+public class SHA512HasherUnitTest {
+
+ private SHA512Hasher hasher;
+ private SecureRandom secureRandom;
+
+ @Before
+ public void setUp() throws Exception {
+ hasher = new SHA512Hasher();
+ secureRandom = new SecureRandom();
+ }
+
+ @Test
+ public void givenSamePasswordAndSalt_whenHashed_checkResultingHashesAreEqual() throws Exception {
+
+ byte[] salt = new byte[16];
+ secureRandom.nextBytes(salt);
+
+ String hash1 = hasher.hash("password", salt);
+ String hash2 = hasher.hash("password", salt);
+
+ assertEquals(hash1, hash2);
+
+ }
+
+ @Test
+ public void givenSamePasswordAndDifferentSalt_whenHashed_checkResultingHashesNotEqual() throws Exception {
+
+ byte[] salt = new byte[16];
+ secureRandom.nextBytes(salt);
+ String hash1 = hasher.hash("password", salt);
+ //generate a second salt
+ byte[] secondSalt = new byte[16];
+ String hash2 = hasher.hash("password", secondSalt);
+
+ assertNotEquals(hash1, hash2);
+
+ }
+
+ @Test
+ public void givenPredefinedHash_whenCorrectAttemptGiven_checkAuthenticationSucceeds() throws Exception {
+ byte[] salt = new byte[16];
+ secureRandom.nextBytes(salt);
+
+ String originalHash = hasher.hash("password123", salt);
+
+ assertTrue(hasher.checkPassword(originalHash, "password123", salt));
+ }
+
+ @Test
+ public void givenPredefinedHash_whenIncorrectAttemptGiven_checkAuthenticationFails() throws Exception {
+ byte[] salt = new byte[16];
+ secureRandom.nextBytes(salt);
+
+ String originalHash = hasher.hash("password123", salt);
+
+ assertFalse(hasher.checkPassword(originalHash, "password124", salt));
+ }
+}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetDateTimeExampleUnitTest.java b/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetDateTimeExampleUnitTest.java
index c60f6967f9..a08d3737cd 100644
--- a/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetDateTimeExampleUnitTest.java
+++ b/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetDateTimeExampleUnitTest.java
@@ -2,9 +2,8 @@ package com.baeldung.zoneddatetime;
import static org.junit.Assert.assertTrue;
-import java.time.LocalDateTime;
import java.time.OffsetDateTime;
-import java.time.ZoneId;
+import java.time.ZoneOffset;
import org.junit.Test;
@@ -14,12 +13,10 @@ public class OffsetDateTimeExampleUnitTest {
@Test
public void givenZoneOffset_whenGetCurrentTime_thenResultHasZone() {
- String zone = "Europe/Berlin";
- OffsetDateTime time = offsetDateTimeExample.getCurrentTimeByZoneOffset(zone);
+ String offset = "+02:00";
+ OffsetDateTime time = offsetDateTimeExample.getCurrentTimeByZoneOffset(offset);
assertTrue(time.getOffset()
- .equals(ZoneId.of(zone)
- .getRules()
- .getOffset(LocalDateTime.now())));
+ .equals(ZoneOffset.of(offset)));
}
}
diff --git a/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetTimeExampleUnitTest.java b/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetTimeExampleUnitTest.java
index 0e1206dc5b..488f934179 100644
--- a/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetTimeExampleUnitTest.java
+++ b/core-java/src/test/java/com/baeldung/zoneddatetime/OffsetTimeExampleUnitTest.java
@@ -2,9 +2,8 @@ package com.baeldung.zoneddatetime;
import static org.junit.Assert.assertTrue;
-import java.time.LocalDateTime;
import java.time.OffsetTime;
-import java.time.ZoneId;
+import java.time.ZoneOffset;
import org.junit.Test;
@@ -14,12 +13,10 @@ public class OffsetTimeExampleUnitTest {
@Test
public void givenZoneOffset_whenGetCurrentTime_thenResultHasZone() {
- String zone = "Europe/Berlin";
- OffsetTime time = offsetTimeExample.getCurrentTimeByZoneOffset(zone);
+ String offset = "+02:00";
+ OffsetTime time = offsetTimeExample.getCurrentTimeByZoneOffset(offset);
assertTrue(time.getOffset()
- .equals(ZoneId.of(zone)
- .getRules()
- .getOffset(LocalDateTime.now())));
+ .equals(ZoneOffset.of(offset)));
}
}
diff --git a/core-java/src/test/java/com/baeldung/zoneddatetime/ZoneDateTimeExampleUnitTest.java b/core-java/src/test/java/com/baeldung/zoneddatetime/ZoneDateTimeExampleUnitTest.java
index 7f4f9cd17c..e78ff3e3fd 100644
--- a/core-java/src/test/java/com/baeldung/zoneddatetime/ZoneDateTimeExampleUnitTest.java
+++ b/core-java/src/test/java/com/baeldung/zoneddatetime/ZoneDateTimeExampleUnitTest.java
@@ -15,16 +15,19 @@ public class ZoneDateTimeExampleUnitTest {
public void givenZone_whenGetCurrentTime_thenResultHasZone() {
String zone = "Europe/Berlin";
ZonedDateTime time = zoneDateTimeExample.getCurrentTimeByZoneId(zone);
+
assertTrue(time.getZone()
.equals(ZoneId.of(zone)));
}
-
+
@Test
public void givenZones_whenConvertDateByZone_thenGetConstantDiff() {
String sourceZone = "Europe/Berlin";
String destZone = "Asia/Tokyo";
ZonedDateTime sourceDate = zoneDateTimeExample.getCurrentTimeByZoneId(sourceZone);
ZonedDateTime destDate = zoneDateTimeExample.convertZonedDateTime(sourceDate, destZone);
- assertTrue(sourceDate.toInstant().compareTo(destDate.toInstant()) == 0);
+
+ assertTrue(sourceDate.toInstant()
+ .compareTo(destDate.toInstant()) == 0);
}
}
diff --git a/java-strings/pom.xml b/java-strings/pom.xml
index 2afe18f07a..29e992a2ce 100644
--- a/java-strings/pom.xml
+++ b/java-strings/pom.xml
@@ -52,6 +52,11 @@