Converting a date string to a DateTime object using Joda Time library

Question

Use DateTimeFormat:

DateTimeFormatter formatter = DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss");
DateTime dt = formatter.parseDateTime(string);

I know this is an old question, but I wanted to add that, as of JodaTime 2.0, you can do this with a one-liner:

DateTime date = DateTime.parse("04/02/2011 20:27:05", 
                  DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss"));

DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss").parseDateTime("04/02/2011 20:27:05");

From comments I picked an answer like and also adding TimeZone:

String dateTime = "2015-07-18T13:32:56.971-0400";

DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZZ")
        .withLocale(Locale.ROOT)
        .withChronology(ISOChronology.getInstanceUTC());

DateTime dt = formatter.parseDateTime(dateTime);

Your format is not the expected ISO format, you should try

DateTimeFormatter format = DateTimeFormat.forPattern("dd/MM/yyyy HH:mm:ss");
DateTime time = format.parseDateTime("04/02/2011 20:27:05");

You can also use SimpleDateFormat, as in DateTimeFormat

Date startDate = null;
Date endDate = null;
try {
    if (validDateStart!= null) startDate = new SimpleDateFormat("MM/dd/yyyy HH:mm", Locale.ENGLISH).parse(validDateStart + " " + validDateStartTime);
    if (validDateEnd!= null) endDate = new SimpleDateFormat("MM/dd/yyyy HH:mm", Locale.ENGLISH).parse(validDateEnd + " " + validDateEndTime);
} catch (ParseException e) {
    e.printStackTrace();
}

tl;dr

java.time.LocalDateTime.parse( 
    "04/02/2011 20:27:05" , 
    DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" )
)

java.time

The modern approach uses the java.time classes that supplant the venerable Joda-Time project.

Parse as a LocalDateTime as your input lacks any indicator of time zone or offset-from-UTC.

String input = "04/02/2011 20:27:05" ;
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu HH:mm:ss" ) ;
LocalDateTime ldt = LocalDateTime.parse( input , f ) ;

ldt.toString(): 2011-02-04T20:27:05

Tip: Where possible, use the standard ISO 8601 formats when exchanging date-time values as text rather than format seen here. Conveniently, the java.time classes use the standard formats when parsing/generating strings.

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About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

• Java SE 8, Java SE 9, and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.